Merge branch 'feat/admin-username-min-length-and-docs'

Lower the username floor to 3 characters on the admin-only write path
(account/channel set-username), separate from the 5-character self-service
minimum, since a deliberately short operator handle isn't the squatting the
higher floor guards against. Channel admin username assignment previously
had no length/format validation at all; this adds it.

Also adds three reference docs: the client's deep-link (tg://, owpg://)
surface, an OpenAPI 3.1 spec for both admin HTTP APIs (built from source,
not the stale docs/admin-panel-api.en.md), and a starter reserved-username
blocklist.

docs/deep-links.md

@@ -0,0 +1,119 @@
+# Client deep links
+
+The desktop client (`owpengram-desktop-client`, a Telegram Desktop fork) resolves
+`tg://<path>` URIs and `https://t.me/<path>` links through the same handler table:
+`Telegram/SourceFiles/core/local_url_handlers.cpp`. Both schemes are normalized to the
+same `<path>?<query>` form before dispatch, so every entry below works as either
+`tg://join?invite=...` or `t.me/join/...` (the client also accepts the shorter
+`t.me/+...` / `t.me/joinchat/...` aliases, which get rewritten to `join?invite=`
+before reaching this table).
+
+Patterns are matched in order top to bottom; the first regex match wins.
+
+## Path handlers
+
+| Path | Handler | Purpose |
+|---|---|---|
+| `join?invite=<hash>` | `JoinGroupByHash` | Join a chat/channel via invite link hash. |
+| `addlist?slug=<slug>` | `JoinFilterBySlug` | Import a shareable chat folder. |
+| `addstickers?set=<name>` / `addemoji?set=<name>` | `ShowStickerSet` | Open a sticker or custom-emoji set for install. |
+| `addtheme?slug=<slug>` | `ShowTheme` | Open a shared theme for install. |
+| `addstyle?slug=<slug>` | `ShowAiStyle` | Open a shared AI compose style. |
+| `setlanguage?lang=<code>` | `SetLanguage` | Switch/install the app's interface language. |
+| `msg_url?<params>` | `ShareUrl` | Open the "share to chat" composer for an external URL. |
+| `confirmphone?<params>` | `ConfirmPhone` | Confirm a phone number transfer/login code sent by SMS. |
+| `socks?<params>` | `ApplySocksProxy` | Add/apply a SOCKS5 proxy config. |
+| `proxy?<params>` | `ApplyMtprotoProxy` | Add/apply an MTProto proxy config. |
+| `webproxy?<params>` | `ApplyWebProxy` | Add/apply a web proxy config. |
+| `passport?<params>` | `ShowPassport` | Telegram Passport authorization request. |
+| `bg?<params>` | `ShowWallPaper` | Open a shared chat wallpaper for install. |
+| `resolve?<params>` | `ResolveUsernameOrPhone` | Resolve `@username`/phone to a peer; see [resolve parameters](#resolve-parameters) below. This is the most common deep link kind. |
+| `privatepost?<params>` | `ResolvePrivatePost` | Open a specific message inside a private channel by internal channel id + message id. |
+| `test_chat_theme?<params>` | `ResolveTestChatTheme` | Preview a chat theme without installing it. |
+| `invoice?<params>` | `ResolveInvoice` | Open a payment invoice (Telegram Payments / Stars). |
+| `premium_offer[?<params>]` | `ResolvePremiumOffer` | Open the Premium subscription offer screen. |
+| `premium_multigift?<params>` | `ResolvePremiumMultigift` | Open the bulk/multi-recipient Premium gifting screen. |
+| `login?code=<n>` | `ResolveLoginCode` | Apply a login confirmation code (QR/code login flow). |
+| `boost?<params>` | `ResolveBoost` | Open the "boost this channel" flow. |
+| `message?slug=<slug>` | `ResolveChatLink` | Open a pre-composed shareable chat/business link. |
+| `stars_topup?<params>` | `ResolveTopUp` | Open the Telegram Stars top-up screen. |
+| `nft?slug=<slug>` | `ResolveUniqueGift` | Open a collectible/unique gift by slug. |
+| `stargift_auction?slug=<slug>` | `ResolveGiftAuction` | Open a Star Gift auction listing. |
+| `call?slug=<slug>` | `ResolveConferenceCall` | Join a group/conference call by invite slug. |
+| `stars[?<params>]` | `ResolveStarsSettings` | Open Telegram Stars balance/settings. |
+| `ton[?<params>]` / `grams[?<params>]` | `ResolveTonSettings` | Open TON wallet settings. |
+| `oauth?<params>` | `ResolveOAuth` | Third-party OAuth authorization via Telegram. |
+| *(anything else)* | `HandleUnknown` | Fallback — shown as an unrecognized-link message. |
+
+## Resolve parameters
+
+`resolve?domain=<username>` (or the bare `t.me/<username>` shorthand, which the
+client rewrites to this form) accepts additional query parameters that change what
+opens once the peer is resolved:
+
+| Parameter | Effect |
+|---|---|
+| `domain` | The `@username` to resolve (required unless using the bare `t.me/<username>` form). |
+| `phone` | Resolve by phone number instead of username. |
+| `appname` | Open a Telegram Mini App by name instead of the peer's chat. |
+| `startapp` | Start-parameter passed into a Mini App launch. |
+| `attach` | Open the target's attach-menu bot alongside the chat. |
+| `start` | Start-parameter for a bot (`/start <token>`). |
+| `startgroup` | Add a bot to a group with this start token (bot-in-group flow). |
+| `startchannel` | Add a bot to a channel with this start token. |
+| `post` | Jump to a specific message id in the resolved peer. |
+| `story` | Open a specific story id from the resolved peer. |
+| `comment` | Jump to a specific comment/reply message id (discussion groups). |
+| `topic` | Open a specific forum topic id. |
+| `thread` | Open a specific reply thread/topic id (older alias of `topic`). |
+| `game` | Launch a specific inline game short name from a bot. |
+| `text` | Pre-fill the message composer with this text. |
+| `voicechat` / `videochat` / `livestream` | Join the peer's active voice chat / video chat / live stream by hash. |
+
+## Internal-only links
+
+`InternalUrlHandlers()` in the same file (`internal:<path>`) covers links the app
+generates for its own in-app UI (e.g. `internal:edit_peer/<id>`,
+`internal:common_groups/<id>`, `internal:collectible_username/<name>@<id>`). These
+are not meant to be shared externally and are not part of the public deep-link
+surface — they only work as links the client itself produces inside its own UI.
+
+## OwpenGram (`owpg://`) links
+
+This fork adds a second scheme, handled in `Telegram/SourceFiles/core/application.cpp`
+(`Application::openLocalUrl` / `Application::openOwpengramUrl`), for operating across
+multiple OwpenGram-compatible backends rather than only the official Telegram DCs.
+
+| Form | Purpose |
+|---|---|
+| `owpg://addserver?host=<host>&port=<port>` | Opens `AddServerBox` pre-filled with just the address. **Deliberately carries nothing else** — no name, description, RSA key, or DC id. |
+| `owpg://oauth?<params>` / `owpg://resolve?<params>` | Rewritten to the equivalent `tg://oauth` / `tg://resolve` command and dispatched on the current session — lets those two flows work on an OwpenGram account, not just official Telegram. |
+| `owpg://<host>/<rest>` | Routes a normal `t.me`-style path (`<rest>` = `+<invite>`, `<username>`, etc.) to whichever logged-in account is on that server's `<host>`, bypassing the official-Telegram-only guard. If no account on the device is logged into `<host>`, the client shows an inform box naming the server instead of silently failing. |
+
+### Why `addserver` only takes host+port
+
+The RSA public key, main DC id, display name, and description are **never** accepted
+from the link itself — see the comment above `kOwpgAddServerRe` in `application.cpp`.
+Letting a link author supply the key/identity directly would be a MITM vector: whoever
+crafts the link would control what the victim ends up trusting as that server's
+identity, regardless of who actually operates the host. Only host+port travel in the
+link; everything else is fetched live and is exactly as trustworthy as the TCP
+connection to that host:port already is.
+
+Once `AddServerBox` has host+port, it calls `Owpengram::FetchServerInfo(host, port, …)`,
+which does a plain HTTP `GET` against the server's own well-known endpoints on the
+same port:
+
+| Endpoint | Returns |
+|---|---|
+| `GET <host>:<port>/owpengram/server-info` | RSA public key (PEM), main DC id, and optional operator-set name/description/icon-presence flag. |
+| `GET <host>:<port>/owpengram/server-icon` | Raw icon bytes, only fetched when `server-info` reported `hasIcon: true`. |
+
+`RefreshServersInfo()` re-polls `server-info`/`server-icon` for every already-added
+custom server to keep a cosmetic name/icon change in sync — it never touches host,
+port, RSA key, DC id, or the server's local id, for the same MITM reason as above (see
+the doc comment on `RefreshServersInfo` in `owpengram_servers.h`).
+
+This also means the RSA-key-in-a-URL scheme discussed earlier in this doc's history
+is intentionally **not** how this client adds a server — that was a plausible-looking
+design that this project already considered and rejected in favor of fetch-after-add.

docs/reserved-usernames.md

@@ -0,0 +1,73 @@
+# Suggested reserved usernames
+
+A starter blocklist for `TELESRV_RESERVED_USERNAMES` (see
+`internal/config/config.go`, `ReservedUsernames`), beyond the shipped
+default (`owpengram, admin, administrator, support, staff, moderator,
+official, root, owner`). The mechanism blocks these, case-insensitively,
+from self-service `account.updateUsername` / `channels.updateUsername` —
+an operator can still assign one deliberately from the admin panel, since
+that's not the squatting this exists to stop.
+
+Organized by why each entry is worth blocking. Trim or extend per your own
+deployment — none of this is enforced by the server itself, it's just a
+starting list to feed into the env var.
+
+## Official-sounding / staff-impersonation
+
+Names that would read as "this account speaks for the operator" if a
+random user grabbed them.
+
+```text
+telegram, telegramofficial, telegramsupport, telegramteam, telegramstaff,
+telegramhq, telegramnews, telegramnotifications, telegramverify, telegrambot,
+telegramservice, security, securityteam, verify, verification, verified,
+helpdesk, helpcenter, customerservice, customersupport, servicedesk, service,
+system, systemmessage, systembot, notifications, notification, alerts,
+announcements, announcement, newsroom, press, pressoffice, spambot, antispam,
+abuse, abusereport, reports, legal, compliance, billing, payments, finance,
+accounts, accountservices, recovery, unlock, restore, backup, headquarters,
+staffteam, modteam, moderation, moderators, founder, cofounder, management
+```
+
+## Founders / executives (real people this server is not affiliated with)
+
+Blocks an account from presenting as Telegram's actual leadership.
+
+```text
+durov, pavel, paveldurov, pdurov, nikolai, nikolaidurov, ndurov, durovpavel,
+telegramceo, telegramfounder
+```
+
+## Crypto / scam-bait
+
+The classic "free crypto giveaway" impersonation targets — official-sounding
+project/exchange names, plus generic scam-pattern handles.
+
+```text
+bitcoin, ethereum, toncoin, tonwallet, tonfoundation, crypto, cryptowallet,
+wallet, airdrop, giveaway, bonus, freecoins, claim, claimnow, binance,
+coinbase, kraken, metamask, trustwallet, ledger, opensea, uniswap, elonmusk,
+tesla, spacex, cryptosupport, walletsupport, tonsupport, binancesupport,
+investment, investmentteam, forextrading, tradingbot, signals, cryptosignals
+```
+
+## Suggested env var
+
+Comma-separated, matching `envListOr`'s parsing:
+
+```bash
+TELESRV_RESERVED_USERNAMES=owpengram,admin,administrator,support,staff,moderator,official,root,owner,telegram,telegramofficial,telegramsupport,telegramteam,telegramstaff,telegramhq,telegramnews,telegramnotifications,telegramverify,telegrambot,telegramservice,security,securityteam,verify,verification,verified,helpdesk,helpcenter,customerservice,customersupport,servicedesk,service,system,systemmessage,systembot,notifications,notification,alerts,announcements,announcement,newsroom,press,pressoffice,spambot,antispam,abuse,abusereport,reports,legal,compliance,billing,payments,finance,accounts,accountservices,recovery,unlock,restore,backup,headquarters,staffteam,modteam,moderation,moderators,founder,cofounder,management,durov,paveldurov,pdurov,nikolai,nikolaidurov,ndurov,durovpavel,telegramceo,telegramfounder,bitcoin,ethereum,toncoin,tonwallet,tonfoundation,crypto,cryptowallet,wallet,airdrop,giveaway,bonus,freecoins,claim,claimnow,binance,coinbase,kraken,metamask,trustwallet,ledger,opensea,uniswap,elonmusk,tesla,spacex,cryptosupport,walletsupport,tonsupport,binancesupport,investment,investmentteam,forextrading,tradingbot,signals,cryptosignals
+```
+
+## What this doesn't cover
+
+- **Collectible usernames** (`internal/admin/service.go` collectible-username
+  actions) go through the admin panel/Admin API directly and aren't gated
+  by this list at all — an operator minting one bypasses it on purpose.
+- **Prefix/substring squatting** (`telegram_real`, `xtelegram`, `te1egram`)
+  — the blocklist is an exact-match (case-insensitive) list, not a pattern
+  matcher, so lookalike spellings need their own entries if you want them
+  blocked too.
+- This is a *username* blocklist only — it says nothing about display
+  names, bios, or profile photos, which can impersonate just as easily and
+  aren't restricted by `TELESRV_RESERVED_USERNAMES` at all.

internal/app/channels/service.go

@@ -635,11 +635,19 @@ func (s *Service) AdminSetSettings(ctx context.Context, channelID int64, patch d
 	return s.channels.SetChannelAdminSettings(ctx, channelID, patch)
 }
 
-// AdminSetUsername force-sets or clears a channel username through the admin path.
+// AdminSetUsername force-sets or clears a channel username through the admin
+// path. Unlike UpdateUsername it does not consult config.ReservedUsernames --
+// an operator who deliberately reserved a word still needs to be able to hand
+// it to a specific channel -- but format/length validity is still enforced,
+// just against the lower minChannelUsernameLenAdmin floor.
 func (s *Service) AdminSetUsername(ctx context.Context, channelID int64, username string) (domain.Channel, error) {
 	if s == nil || s.channels == nil || channelID == 0 {
 		return domain.Channel{}, domain.ErrChannelInvalid
 	}
+	username = normalizeChannelUsername(username)
+	if username != "" && !validChannelUsernameMinLen(username, minChannelUsernameLenAdmin) {
+		return domain.Channel{}, domain.ErrUsernameInvalid
+	}
 	return s.channels.SetChannelUsernameAdmin(ctx, channelID, username)
 }
 
@@ -2520,8 +2528,20 @@ func normalizeChannelUsername(username string) string {
 	return strings.TrimSpace(username)
 }
 
+// minChannelUsernameLenAdmin is the floor for an operator-assigned channel
+// username via AdminSetUsername (the admin API/panel) -- shorter than what
+// self-service channels.updateUsername allows, mirroring
+// users.minUsernameLenAdmin: a deliberate short handle assigned by an
+// operator is not the squatting the higher self-service minimum guards
+// against.
+const minChannelUsernameLenAdmin = 3
+
 func validChannelUsername(username string) bool {
-	if len(username) < 5 || len(username) > 32 {
+	return validChannelUsernameMinLen(username, 5)
+}
+
+func validChannelUsernameMinLen(username string, minLen int) bool {
+	if len(username) < minLen || len(username) > 32 {
 		return false
 	}
 	for i := 0; i < len(username); i++ {

internal/app/users/service.go

@@ -117,6 +117,12 @@ func WithReservedUsernames(names []string) Option {
 
 const (
 	minUsernameLen = 5
+	// minUsernameLenAdmin is the floor for an operator-assigned username via
+	// UpdateUsernameAdmin (the admin API/panel) -- shorter than what self-service
+	// account.updateUsername allows, since a deliberate short handle assigned by
+	// an operator (e.g. a 3-4 char official/brand account) is not the squatting
+	// the higher self-service minimum guards against.
+	minUsernameLenAdmin = 3
 	maxUsernameLen      = 32
 	maxProfileNameRunes = 64
 	// bio 长度双档，对齐 appConfig about_length_limit_default=70 /
@@ -383,7 +389,13 @@ func (s *Service) updateUsername(ctx context.Context, userID int64, username str
 		return s.projectOne(ctx, self.ID, self)
 	}
 	if username != "" {
-		if !validUsername(username) || (enforceReserved && s.reserved.Contains(username)) {
+		minLen := minUsernameLen
+		if !enforceReserved {
+			// enforceReserved=false is exactly the admin-bypass path
+			// (UpdateUsernameAdmin) -- see minUsernameLenAdmin's doc comment.
+			minLen = minUsernameLenAdmin
+		}
+		if !validUsernameMinLen(username, minLen) || (enforceReserved && s.reserved.Contains(username)) {
 			return domain.User{}, domain.ErrUsernameInvalid
 		}
 		var (
@@ -1040,7 +1052,11 @@ func normalizeUsername(username string) string {
 }
 
 func validUsername(username string) bool {
-	if len(username) < minUsernameLen || len(username) > maxUsernameLen {
+	return validUsernameMinLen(username, minUsernameLen)
+}
+
+func validUsernameMinLen(username string, minLen int) bool {
+	if len(username) < minLen || len(username) > maxUsernameLen {
 		return false
 	}
 	for i := 0; i < len(username); i++ {