fix: Complete rewrite of progress tracking system (v1.0.9)

The /ab:build command was executing tasks but not tracking progress.
This rewrite enforces dual progress tracking in BOTH status.json AND plan.md.

Key changes:

build.md - Complete restructure:
- Step-by-step execution workflow (like migrate.md)
- Step 4d MANDATORY: Update both status.json and plan.md
- User confirmation required between tasks
- Visual Progress Tracker table in plan template

planner.md - New plan template:
- Progress Tracker table at top with ⬜/✅ indicators
- Each task has `- **Status**: ⬜ Pending` field
- Status header shows overall progress

coder.md - Dual file updates:
- 5a: Update status.json (currentTask, tasksCompleted, history)
- 5b: Update plan.md Progress Tracker (⬜ Pending → ✅ Done)

Benefits:
- Visual progress in plan.md (human readable)
- JSON progress in status.json (programmatic)
- Redundancy ensures progress is never lost
- Team can see exactly which tasks are complete

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

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

.claude-plugin/marketplace.json

@@ -11,7 +11,7 @@
       "name": "ab",
       "source": "./plugin",
       "description": "Spec-driven build orchestration with git worktree isolation and session memory",
-      "version": "1.0.7",
+      "version": "1.0.9",
       "keywords": ["build", "spec", "automation", "worktree", "qa"]
     }
   ]