Sync architecture.md with shipped capture, probes, adapters

[askmy-stack]

Summary

`docs/architecture.md` is stale relative to shipped work: the pipeline diagram still marks live MCP as planned, and the component table still lists Behavioral runner / Adapter generator as planned even though M1 capture, offline probes, and M6 adapters exist.

Acceptance criteria

• Update mermaid diagram: live MCP is supported (stdio); SSE remains stubbed
• Component table reflects: `mcp_capture`, `probes`, `adapters`, `policy`, `config`, GitHub Action
• Note what remains planned (model-backed runners / M4 matrix)
• Link to `docs/adapters.md`, `docs/adr-live-mcp-capture.md`, `docs/change-codes.md`

Why

New contributors reading architecture get an outdated mental model of the package.