docs: update docs for Teams integration

- USAGE.md: Teams Integration section (config, setup, compat matrix)
- CHEATSHEET.md: Teams config snippet
- API.md: TeamsBot and TeamsMessage reference
- README.md: Teams in features list
- ROADMAP.md: v2.1.0 milestone
- TODO.md/TASKS.md: Teams items

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

ROADMAP.md

@@ -128,3 +128,17 @@
 - [x] `cron` plugin (scheduled bot commands on a timer)
 - [x] Plugin command unit tests (encode, hash, dns, cidr, defang)
 - [x] CI pipeline (Gitea Actions, Python 3.11-3.13, ruff + pytest)
+
+## v2.1.0 -- Teams Integration
+
+- [x] Microsoft Teams adapter via outgoing webhooks (no SDK)
+- [x] `TeamsBot` class with same plugin API as IRC `Bot`
+- [x] `TeamsMessage` dataclass duck-typed with IRC `Message`
+- [x] HMAC-SHA256 webhook signature validation
+- [x] Permission tiers via AAD object IDs
+- [x] IRC-only methods as no-ops (join, part, kick, mode, set_topic)
+- [x] Incoming webhook support for `send()` (proactive messages)
+- [x] Paste overflow via FlaskPaste (same as IRC)
+- [ ] Adaptive Cards for richer formatting
+- [ ] Graph API integration for DMs and richer channel access
+- [ ] Teams event handlers (member join/leave)