docs: document server-side rendering pipeline, response timing middleware, and Telegram pairing API

- Add comprehensive documentation for backend content rendering in AGENTS.md, detailing the new `render_content` and `render_title` Jinja globals built on mistune with media processing, emoji shortcodes, and XSS protection
- Document the `X-Response-Time` header and bottom-left render time indicator in README.md
- Update bot token pricing documentation to clarify fallback vs gateway cost headers
- Add `email_accounts` to soft-delete tables and `idx_users_role` composite index in database schema
- Implement `telegram_pairings` and `telegram_links` table creation with column migration and indexes
- Add `/profile/{username}/telegram` endpoint to docs API with request/unpair actions
- Register `TelegramService` in main.py lifespan and add `response_timing` middleware emitting `X-Response-Time` header
- Introduce `TelegramPairForm` model and `guard_public_host_sync` synchronous host validation function

devplacepy/routers/docs/pages.py

@@ -69,6 +69,12 @@ DOCS_PAGES = [
         "kind": "prose",
         "section": SECTION_GENERAL,
     },
+    {
+        "slug": "telegram",
+        "title": "Devii on Telegram",
+        "kind": "prose",
+        "section": SECTION_GENERAL,
+    },
     {
         "slug": "dashboard",
         "title": "Your dashboard",
@@ -174,6 +180,12 @@ DOCS_PAGES = [
         "kind": "prose",
         "section": SECTION_COMPONENTS,
     },
+    {
+        "slug": "component-dp-title",
+        "title": "dp-title",
+        "kind": "prose",
+        "section": SECTION_COMPONENTS,
+    },
     {
         "slug": "component-dp-upload",
         "title": "dp-upload",
@@ -321,6 +333,13 @@ DOCS_PAGES = [
         "admin": True,
         "section": SECTION_ADMIN,
     },
+    {
+        "slug": "telegram-admin",
+        "title": "Telegram bot operations",
+        "kind": "prose",
+        "admin": True,
+        "section": SECTION_ADMIN,
+    },
     {
         "slug": "media-moderation",
         "title": "Media moderation",