feat: [Phase 5] Remove Python bridge + cleanup

[anandgupta42]

Phase 5: Bridge Removal + Cleanup

Parent: #214
Depends on: All previous phases

What

Remove the Python bridge, engine bootstrap, and altimate-engine package entirely. Zero Python dependency.

Sub-tasks

• ALTIMATE_NATIVE_ONLY=1 bun test — all 77 methods pass
• Cold start benchmark: time altimate-code --version (target: <100ms)
• Clean env test: Docker without Python, Snowflake connect + lint
• Delete packages/altimate-engine/
• Delete packages/opencode/src/altimate/bridge/
• Move types from protocol.ts → native/types.ts
• Remove engine bootstrap (uv, venv, pip)
• Remove ALTIMATE_ENGINE_VERSION constant
• Remove bridge fallback from dispatcher
• Update README.md, docs/docs/troubleshooting.md, RELEASING.md
• Close Python Bridge is failing during initial runs #210

Success Metrics

Metric	Before	After
Cold start	500-800ms	<100ms
Install	Python + pip + venv	npm only
Issue #210	Fails	Works

[anandgupta42]

Completed in PR #221.