feat: add NFT usernames and bot verification (#22)

Implements collectible usernames, official verification workflows, and third-party bot verification after maintainer protocol and migration review.

The composite activity/moderation rating remains an admin-only read model; Telegram Stars Rating wire fields stay unset pending a dedicated official-semantics implementation.

Reviewed-Head: 2796345775ea0f908fb7734601e5e1dee4b653b9
Original-Head: fa082b892fd5180c9c9bc53c81c21cf5d250a75b

Co-authored-by: Egor Egorov <business.egor.sg@gmail.com>

deploy/migrations/0153_verify_service_bot.up.sql

@@ -0,0 +1,89 @@
+-- Built-in @verifybot: the front door for official platform verification.
+--
+-- Seeded here rather than lazily on first message so the username is occupied
+-- from the moment the schema is current: peer_usernames.username_lower is the
+-- only thing standing between a reserved bot handle and an ordinary user
+-- claiming it, and a lazily created account would leave that window open.
+--
+-- access_hash is double-written with domain.VerifyBotAccessHash; the two must
+-- never drift, exactly as for the other service bots (0044, 0045, 0047).
+--
+-- The peer_usernames insert carries the multi-username registry columns added in
+-- 0149, so the handle occupies the editable slot.
+
+INSERT INTO public.users (
+    id, access_hash, phone, first_name, last_name, username, country_code,
+    created_at, updated_at, verified, support, about, last_seen_at,
+    default_history_ttl_period, is_bot, bot_info_version, premium_expires_at,
+    emoji_status_document_id, emoji_status_until, color_set, color,
+    color_background_emoji_id, profile_color_set, profile_color,
+    profile_color_background_emoji_id
+) VALUES (
+    1250000011, 7802113947355620887, '', 'Verify Bot', '', 'verifybot', '',
+    now(), now(), true, false,
+    'Apply for official verification of a public channel, supergroup or bot.',
+    0, 0, true, 1, NULL, 0, 0, false, 0, 0, false, 0, 0
+)
+ON CONFLICT (id) DO UPDATE SET
+    access_hash = EXCLUDED.access_hash,
+    phone = EXCLUDED.phone,
+    first_name = EXCLUDED.first_name,
+    last_name = EXCLUDED.last_name,
+    username = EXCLUDED.username,
+    verified = EXCLUDED.verified,
+    support = EXCLUDED.support,
+    about = EXCLUDED.about,
+    is_bot = EXCLUDED.is_bot,
+    bot_info_version = GREATEST(public.users.bot_info_version, EXCLUDED.bot_info_version),
+    updated_at = now();
+
+INSERT INTO public.bots (
+    bot_user_id, owner_user_id, token_secret, description, commands,
+    bot_chat_history, bot_nochats, inline_placeholder, created_at, updated_at,
+    menu_button_type, menu_button_text, menu_button_url, bot_inline_geo
+) VALUES (
+    1250000011, 1250000011, '',
+    'Apply for official verification of a public channel, supergroup or bot. The bot collects the application and reports the decision back to you.',
+    '[
+        {"command": "start", "description": "how verification works"},
+        {"command": "new", "description": "file a verification application"},
+        {"command": "status", "description": "check your applications"},
+        {"command": "cancel", "description": "cancel the current application"},
+        {"command": "help", "description": "show help"}
+    ]'::jsonb,
+    false, true, '', now(), now(), 0, '', '', false
+)
+ON CONFLICT (bot_user_id) DO UPDATE SET
+    owner_user_id = EXCLUDED.owner_user_id,
+    token_secret = EXCLUDED.token_secret,
+    description = EXCLUDED.description,
+    commands = EXCLUDED.commands,
+    bot_chat_history = EXCLUDED.bot_chat_history,
+    bot_nochats = EXCLUDED.bot_nochats,
+    inline_placeholder = EXCLUDED.inline_placeholder,
+    menu_button_type = EXCLUDED.menu_button_type,
+    menu_button_text = EXCLUDED.menu_button_text,
+    menu_button_url = EXCLUDED.menu_button_url,
+    bot_inline_geo = EXCLUDED.bot_inline_geo,
+    updated_at = now();
+
+INSERT INTO public.peer_usernames (
+    username_lower, username, peer_type, peer_id, active, editable, sort_order, updated_at
+)
+VALUES ('verifybot', 'verifybot', 'user', 1250000011, true, true, 0, now())
+ON CONFLICT (username_lower) DO UPDATE SET
+    username = EXCLUDED.username,
+    peer_type = EXCLUDED.peer_type,
+    peer_id = EXCLUDED.peer_id,
+    active = EXCLUDED.active,
+    editable = EXCLUDED.editable,
+    updated_at = now();
+
+INSERT INTO public.read_model_versions (model, owner_user_id, peer_type, peer_id, version, updated_at, hash)
+VALUES
+    ('contact_account', 1250000011, 'user', 1250000011, 1, now(), 2500001100001),
+    ('channel_active_memberships', 1250000011, 'user', 1250000011, 1, now(), 2500001100002)
+ON CONFLICT (model, owner_user_id, peer_type, peer_id) DO UPDATE SET
+    version = GREATEST(public.read_model_versions.version, EXCLUDED.version),
+    updated_at = now(),
+    hash = EXCLUDED.hash;