Refactor: serve.py is a 3000-line god-module — split into cli/*.py

[tcconnally]

Severity: 🟢 Low (architecture; long-term maintenance)

src/perseus/serve.py is ~3000 lines covering: render, watch, graph, prefetch, synthesize, pack, validate, launchd install, MCP dispatch, cron, systemd, health, doctor, trust, update, oracle, serve HTTP, init.

This is the single biggest correctness/maintainability risk in the codebase. A change to any one command requires reading a massive blast radius.

Suggested decomposition

src/perseus/cli/
    render.py
    watch.py
    synth.py
    pack.py
    install.py
    doctor.py
    trust.py
    update.py
    oracle.py
    serve_http.py
    scheduler.py  (launchd/cron/systemd)

Keep serve.py as a thin re-export shim for backward compatibility. No behavior change — pure refactor. Ship as v1.1.0.

Acceptance criteria

• All existing tests pass without modification.
• git diff shows pure code movement (no logic deltas) per command file.
• Public symbols (cmd_render, cmd_serve, etc.) remain importable from perseus.serve.

[tcconnally]

Deferred to future release — tracked in milestone v1.1+. The v1.0.6 hotfix cycle focused on security/correctness/performance fixes. Enhancement and refactoring issues will be prioritized in the next release cycle.