(2/6) simplify router to mount tools

[philipnee]

Why

The active mvmt runtime is mount-only, but ToolRouter still carried raw proxy routing and the older semantic context adapter layer. That made the router larger than the current product surface and kept tests anchored to behavior we are intentionally moving away from.

What changed

• Simplified ToolRouter to expose only the current mount tools: search, list, read, write, and remove.
• Removed raw connector tool registration and old search_personal_context / read_context_item routing from the router.
• Updated startup to construct the router from the text context index instead of loaded connector entries.
• Reworked router and MCP server tests around mount-tool visibility, path/action policy, plugin processing, and audit logging.

How

ToolRouter now builds tool definitions from TextContextIndex when mounts exist. Per-client permissions are evaluated directly against virtual mount paths, and audit entries consistently use connectorId mvmt for mount tool calls.

Changed files

• src/server/router.ts
• src/cli/start.ts
• tests/router.test.ts
• tests/server.test.ts

Verification

• npm test -- tests/router.test.ts tests/server.test.ts
• npm run verify