fix: correct drift-report.json handling in Titan skills

- Fix self-referential "skip to Step 1" loop in titan-gauntlet drift
  detection (should be Step 2)
- Change drift-report.json from single-object overwrite to JSON array
  append in gauntlet and sync skills, so titan-close can read cumulative
  pipeline history

Author: carlos-alm

.claude/skills/titan-close/SKILL.md

@@ -88,7 +88,7 @@ CLOSE is the last phase — it must assess the full pipeline's freshness before
    git diff --name-only <mainSHA>..origin/main
    ```
 
-3. **Read all prior drift reports** from `.codegraph/titan/drift-report.json`. This shows the cumulative drift across the pipeline.
+3. **Read all prior drift reports** from `.codegraph/titan/drift-report.json` (a JSON array of entries, one per phase that detected drift). This shows the cumulative drift across the pipeline.
 
 4. **Assess overall pipeline freshness:**
 

.claude/skills/titan-gauntlet/SKILL.md

@@ -75,7 +75,7 @@ The codebase may have changed significantly since RECON ran. Detect this before
    ```bash
    git rev-parse origin/main
    ```
-   Compare against `titan-state.json → mainSHA`. If identical, skip to Step 1.
+   Compare against `titan-state.json → mainSHA`. If identical, skip to Step 2.
 
 2. **If main has advanced**, find what changed:
    ```bash
@@ -104,7 +104,7 @@ The codebase may have changed significantly since RECON ran. Detect this before
    | **high** | >20% of batches affected OR core symbols changed | **Warn user:** "Significant changes on main since RECON. Recommend re-running affected batches or `/titan-recon`." |
    | **critical** | New files in src/, deleted files that were in batches, or >50% of priority queue affected | **Stop and recommend:** "Main has diverged significantly. Run `/titan-recon` to rebuild the baseline." |
 
-6. **Write drift report** to `.codegraph/titan/drift-report.json`:
+6. **Append drift report** to `.codegraph/titan/drift-report.json` (the file is a JSON array — read existing entries first, push the new entry, write back):
 
    ```json
    {

.claude/skills/titan-sync/SKILL.md

@@ -102,7 +102,7 @@ The codebase may have changed between GAUNTLET and now. Detect this before plann
    | **high** | >30% of FAIL targets affected OR shared dependencies changed | **Warn user:** "Main has changed significantly since GAUNTLET. Audit results for N targets may be stale. Recommend `/titan-gauntlet` re-run for affected targets before planning." |
    | **critical** | New files added to src/ that would be in priority queue, or deleted files that were FAIL targets | **Stop:** "Codebase structure changed. Run `/titan-recon` to rebuild baseline, then `/titan-gauntlet`." |
 
-5. **Write/update drift report** to `.codegraph/titan/drift-report.json` (same schema as GAUNTLET, with `"detectedBy": "sync"`).
+5. **Append drift report** to `.codegraph/titan/drift-report.json` (the file is a JSON array — read existing entries, push the new entry, write back; same schema as GAUNTLET, with `"detectedBy": "sync"`).
 
 6. **Update state:** Set `titan-state.json → mainSHA` to current `origin/main`.