feat: ambient mode — proportional quality enforcement

[dean0x]

Summary

• New plugin: devflow-ambient with /ambient command for one-shot or always-on proportional quality enforcement
• New skills: ambient-router (intent/depth classification into QUICK/STANDARD/ESCALATE tiers) and test-driven-development (TDD enforcement auto-activates for BUILD/STANDARD depth)
• Always-on mode: devflow ambient --enable registers a UserPromptSubmit hook that classifies every prompt and loads proportional skills — zero overhead for quick tasks, full enforcement for complex ones
• Interactive install: devflow init now prompts for ambient mode (with --ambient/--no-ambient CLI flags)
• Clean uninstall: Full uninstall removes ambient hook unconditionally before the blanket hooks prompt, so it's cleaned even if user preserves other hooks. Selective --plugin=ambient uninstall also cleans the hook.
• Memory improvements: patterns.md extraction in background hook and injection in session-start hook for cross-session pattern continuity
• 19 new tests (137 total across 9 test files): 16 ambient settings manipulation tests + 3 re-export verification tests

Changes

Area	Files	What
Skills	shared/skills/ambient-router/, shared/skills/test-driven-development/	New skills (26 total)
Plugin	plugins/devflow-ambient/	New plugin with /ambient command (9 plugins total)
CLI	src/cli/commands/ambient.ts, src/cli/cli.ts, src/cli/plugins.ts	devflow ambient --enable/--disable/--status
Install	src/cli/commands/init.ts	--ambient/--no-ambient flags + interactive prompt
Uninstall	src/cli/commands/uninstall.ts	Unconditional ambient hook cleanup in full uninstall
Hooks	scripts/hooks/ambient-prompt.sh	UserPromptSubmit hook (skip slash commands & short confirmations)
Memory	scripts/hooks/background-memory-update.sh, scripts/hooks/session-start-memory.sh	patterns.md extraction/injection
Docs	README.md, CLAUDE.md, CONTRIBUTING.md, marketplace.json	Updated for 9 plugins, 26 skills
Tests	tests/ambient.test.ts, tests/init-logic.test.ts	19 new tests

Test plan

• npm run build — 26 skills distributed across 9 plugins
• npm test — 137/137 pass
• node dist/cli.js init --ambient — ambient hook appears in settings.json
• node dist/cli.js init --no-ambient — no ambient hook
• node dist/cli.js ambient --status — reports enabled/disabled
• devflow uninstall → NO to hooks → ambient hook still removed, other hooks preserved
• devflow uninstall --plugin=ambient → ambient hook removed