[WIP] feat: Task size classification (suppress heavy orchestration)

[quangdang46]

Gap #21 — Medium

Classify user prompts as small/medium/large and suppress heavy orchestration for simple tasks.

Source: oh-my-codex

What's needed:

• Escape hatch prefixes: quick:, simple:, tiny:, minor:, small:, just:, only:
• Small task signals: regex for "typo", "rename", "single file", "one-liner"
• Large task signals: regex for "architecture", "refactor", "from scratch", "migration"
• Word count thresholds: <50 words = small, >200 words = large
• Suppress heavy orchestration (swarm, multi-agent) for small tasks

Reference: oh-my-codex src/hooks/task-size-detector.ts