Complete: P0+P1+P2+Skills (2189 lines, 22 features)

P0+P1 complete: approval, background tasks, custom agents, auto git commit

P0: /init + tool budget reduction + error recovery + auto-verify + hooks

v4: Add OpenAI Codex integration + unified model factory

v4: Claude Code 4-layer memory (instructions + memory + session + compact)

Add CodePilot v4: duel toggle, context memory, LeetCode auto-grind