[Coda] Add structured workspace command action

[George Ng (GeorgeNgMsft)]

Summary

Adds an action to directly run structured commands for the VS Code Coda integration and MCP clients. Allows the user to conveniently run their build commands quickly and in the same window as TypeAgent.
Structured command: run command pnpm run build or execute command pnpm run lint uses the new grammar and structured runner.

Examples :

• Exposes typed
  un_workspace_command and cancel_workspace_command MCP tools with structured output.
• Runs bounded focused build, test, lint, and diagnostic commands in exactly one connected workspace.
• Returns stdout, stderr, exit code, duration, timeout, cancellation, and truncation metadata; includes safe cancellation and process cleanup.
• Preserves the existing integrated-terminal behavior while adding schema, grammar, documentation, and focused tests.

Validation

• pnpm --filter agent-coda run build && pnpm --filter agent-coda run test:local
• pnpm --filter @typeagent/code-agent run build plus targeted result-relay test
• pnpm --filter command-executor-mcp run build plus targeted MCP schema test
• Prettier and lint, complexity, circular-dependency, and debt ratchets