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/admin/users.py

@@ -19,7 +19,7 @@ from devplacepy.utils import (
 )
 from devplacepy.seo import base_seo_context, site_url, website_schema
 from devplacepy.responses import respond, action_result
-from devplacepy.schemas import AdminUsersOut
+from devplacepy.schemas import AdminUsersOut, UserAiUsageOut
 from devplacepy.services.audit import record as audit
 from devplacepy.services.manager import service_manager
 from devplacepy.services.openai_gateway.analytics import build_user_usage
@@ -62,7 +62,8 @@ async def admin_user_ai_usage(request: Request, uid: str, hours: int = 24):
         return JSONResponse({"error": "Admin access required"}, status_code=403)
     service = service_manager.get_service("openai")
     pricing = pricing_from_cfg(service.get_config()) if service is not None else None
-    return JSONResponse(build_user_usage(uid, hours=hours, pricing=pricing))
+    usage = build_user_usage(uid, hours=hours, pricing=pricing)
+    return JSONResponse(UserAiUsageOut(**usage).model_dump())
 
 @router.get("/users", response_class=HTMLResponse)
 async def admin_users(request: Request, page: int = 1):