chore(skills): Auto-generate .claude/skills mirror from .agents/skills

[leviem1]

Makes the tracked sources the single source of truth for the Claude-Code-facing files, and treats the copies Claude Code consumes as generated, gitignored output:

• Skills: .agents/skills/ is canonical (shared with other agents). .claude/skills/ is a generated mirror — Claude Code only discovers skills there.
• Project instructions: AGENTS.md is canonical. CLAUDE.md is a generated copy of it.

This removes the byte-identical committed duplicates and the manual cp workflow that had already drifted.

How it works

• .claude/hooks/sync-agent-files.sh regenerates both outputs: it mirrors .agents/skills/ → .claude/skills/ (wiping stale/renamed folders) and copies AGENTS.md → CLAUDE.md.
• .claude/settings.json runs it on SessionStart (with reloadSkills so mirrored skills load in-session) and on PostToolUse after edits under .agents/skills/** or to AGENTS.md.
• .gitattributes pins *.sh to LF so the hook script runs under Git Bash on Windows.

Cleanup

• Removed the update-local-skills skill (both trees).
• Untracked the generated copies: the fill-template-plugin / run-plugin skill mirror, and CLAUDE.md (was a tracked @AGENTS.md import; now a full generated copy, gitignored alongside the skill mirror).

Verified

• sh .claude/hooks/sync-agent-files.sh regenerates the mirror (only fill-template-plugin/ + run-plugin/, stale dirs self-heal) and writes a CLAUDE.md identical to AGENTS.md.
• git check-ignore confirms .claude/skills/* and CLAUDE.md are ignored.
• The SessionStart run emits the reloadSkills JSON.
• git status is clean — no generated files tracked.