fix: Symlink .auto-build-data/ and .claude/rules/ in worktrees

Worktrees now have symlinks to the main repo's:
- .auto-build-data/ - specs, plans, status, memory
- .claude/rules/ - auto-build patterns and learned memory

This ensures /ab:build can detect PLANNING_COMPLETE status when
running in worktree and continue with implementation.

Also clarified in build.md that PLANNING_COMPLETE skips planning.

Bumps version to 1.0.5.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

plugin/.claude-plugin/plugin.json

@@ -1,7 +1,7 @@
 {
   "name": "ab",
   "description": "Auto-Build: Spec-driven build orchestration with worktree isolation and session memory",
-  "version": "1.0.4",
+  "version": "1.0.5",
   "author": {
     "name": "ROA2WEB Team"
   }