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>

docs/API.md

@@ -228,6 +228,66 @@ Wire-format encode/decode for raw DNS queries and responses.
 
 ---
 
+## `derp.teams` -- Teams Adapter
+
+Alternative bot adapter for Microsoft Teams via outgoing/incoming webhooks.
+Exposes the same plugin API as `derp.bot.Bot` so protocol-agnostic plugins
+work without modification.
+
+### `TeamsMessage` dataclass
+
+Duck-typed compatible with IRC `Message`:
+
+| Field | Type | Description |
+|-------|------|-------------|
+| `raw` | `dict` | Original Activity JSON |
+| `nick` | `str \| None` | Sender display name |
+| `prefix` | `str \| None` | Sender AAD object ID (for ACL) |
+| `text` | `str \| None` | Message body (stripped of @mention) |
+| `target` | `str \| None` | Conversation/channel ID |
+| `is_channel` | `bool` | Always `True` (outgoing webhooks) |
+| `command` | `str` | Always `"PRIVMSG"` (compat shim) |
+| `params` | `list[str]` | `[target, text]` |
+| `tags` | `dict[str, str]` | Empty dict (no IRCv3 tags) |
+| `_replies` | `list[str]` | Reply buffer (unstable) |
+
+### `TeamsBot`
+
+Same stable attributes and methods as `Bot`:
+
+| Attribute | Type | Description |
+|-----------|------|-------------|
+| `name` | `str` | Always `"teams"` |
+| `config` | `dict` | Merged TOML configuration |
+| `nick` | `str` | Bot display name (`teams.bot_name`) |
+| `prefix` | `str` | Command prefix (from `[bot]`) |
+| `state` | `StateStore` | Persistent key-value storage |
+| `registry` | `PluginRegistry` | Shared command and event registry |
+
+**Sending messages** -- same signatures, different transport:
+
+| Method | Behaviour |
+|--------|-----------|
+| `send(target, text)` | POST to incoming webhook URL |
+| `reply(msg, text)` | Append to `msg._replies` (HTTP response) |
+| `long_reply(msg, lines, *, label="")` | Paste overflow, appends to replies |
+| `action(target, text)` | Italic text via incoming webhook |
+| `shorten_url(url)` | Same FlaskPaste integration |
+
+**IRC no-ops** (debug log, no error):
+
+`join`, `part`, `kick`, `mode`, `set_topic`
+
+**Plugin management** -- delegates to shared registry:
+
+`load_plugins`, `load_plugin`, `reload_plugin`, `unload_plugin`
+
+**Permission tiers** -- same model, exact AAD object ID matching:
+
+`_get_tier(msg)`, `_is_admin(msg)`
+
+---
+
 ## Handler Signatures
 
 All command and event handlers are async functions receiving `bot` and