docs: post-agent-bus housekeeping (#57)

[UroojFatima-052]

Refs #57

Post-#55 agent bus housekeeping across the docs.

Changes

• docs/development/roadmap.md : added Motion & triggers follow-ups: Agent bus outbound WebSocket state events (#59) and Agent bus window/file audio source via API (#56). [Feature]: Local agent/event bus so external tools can drive the avatar #6 and [Feature]: Reactive glass-bar live dot (amplitude + capture status colors) #42 already marked [x] on main. No MCP entry since [Feature]: MCP server adapter over the local agent bus (HTTP) #61 shipped in v0.8.0.
• docs/user-settings.md : added ### Agents (agentBus) subsection under "What is saved," matching the shape of the Motion Deck subsection. Covers panel location, enabled/port/requireToken fields, token storage in agent-bus.json, copy/regenerate flow, and cross-link to docs/agents/local-bus.md. Screenshot uses a placeholder pending [Docs]: Visual overhaul — reshoot companion screenshots & GIFs (batched)` #33.
• docs/agents/local-bus.md : added cross-link back to user-settings.md#agents-agentbus under the closing config.yaml section.
• README.md : added Agents to the top nav strip; added Integrations row to the Documentation table linking to local-bus.md.
• docs/using-the-app.md : no change; the existing ### Agents (desktop) subsection under Settings already covers the pointer.
• CHANGELOG.md : [Unreleased] > Changed entry for the housekeeping.

Notes

• No product code changes.
• Verified feat(agent-bus): local loopback command API for agents and scripts #55 CHANGELOG entry under v0.8.0 is complete (thorough coverage of loopback bus, WebSocket, token handling, Origin refusal, MCP).