msteams: implement Teams AI agent UX best practices (#51808)

Migrates the Teams extension from @microsoft/agents-hosting to the official Teams SDK (@microsoft/teams.apps + @microsoft/teams.api) and implements Microsoft's AI UX best practices for Teams agents.

- AI-generated label on all bot messages (Teams native badge + thumbs up/down)
- Streaming responses in 1:1 chats via Teams streaminfo protocol
- Welcome card with configurable prompt starters on bot install
- Feedback with reflective learning (negative feedback triggers background reflection)
- Typing indicators for personal + group chats (disabled for channels)
- Informative status updates (progress bar while LLM processes)
- JWT validation via Teams SDK createServiceTokenValidator
- User-Agent: teams.ts[apps]/<sdk-version> OpenClaw/<version> on outbound requests
- Fix copy-pasted image downloads (smba.trafficmanager.net auth allowlist)
- Pre-parse auth gate (reject unauthenticated requests before body parsing)
- Reflection dispatcher lifecycle fix (prevent leaked dispatchers)
- Colon-safe session filenames (Windows compatibility)
- Cooldown cache eviction (prevent unbounded memory growth)

Closes #51806

scripts/tsdown-build.mjs

@@ -49,7 +49,7 @@ function findFatalUnresolvedImport(lines) {
     }
 
     const normalizedLine = line.replace(ANSI_ESCAPE_RE, "");
-    if (!normalizedLine.includes("extensions/")) {
+    if (!normalizedLine.includes("extensions/") && !normalizedLine.includes("node_modules/")) {
       return normalizedLine;
     }
   }