docs: add cursor to changesets config and documentation

- Add @composio/ao-plugin-agent-cursor to linked version group in .changeset/config.json
- Update README.md plugin architecture table to include cursor
- Update config.md reference to include cursor in agent options

This ensures the cursor plugin versions in lockstep with other built-in plugins
and is properly documented for users.

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

.changeset/config.json

@@ -13,6 +13,7 @@
       "@composio/ao-plugin-agent-claude-code",
       "@composio/ao-plugin-agent-codex",
       "@composio/ao-plugin-agent-aider",
+      "@composio/ao-plugin-agent-cursor",
       "@composio/ao-plugin-agent-opencode",
       "@composio/ao-plugin-workspace-worktree",
       "@composio/ao-plugin-workspace-clone",

README.md

@@ -145,7 +145,7 @@ Seven plugin slots. Lifecycle stays in core.
 | Slot      | Default     | Alternatives             |
 | --------- | ----------- | ------------------------ |
 | Runtime   | tmux        | process                  |
-| Agent     | claude-code | codex, aider, opencode   |
+| Agent     | claude-code | codex, aider, cursor, opencode   |
 | Workspace | worktree    | clone                    |
 | Tracker   | github      | linear, gitlab           |
 | SCM       | github      | gitlab                   |

skills/agent-orchestrator/references/config.md

@@ -15,7 +15,7 @@ readyThresholdMs: 300000      # Ms before "ready" session becomes "idle" (5 min)
 ```yaml
 defaults:
   runtime: tmux               # tmux | process
-  agent: claude-code          # claude-code | aider | codex | opencode
+  agent: claude-code          # claude-code | aider | codex | cursor | opencode
   workspace: worktree         # worktree | clone
   notifiers:                  # Active notifier plugins
     - desktop                 # desktop | slack | webhook | composio | openclaw