docs(deepagent): m29c refresh M28 panel secrets_scan for DCOV-007

Durable verify only: re-scan panel_prod_hard_deepswe_med_m28 (hit_count=0).
No pier re-eval; scoreboard gates already satisfied.

Author: echobt

deepagent/datasets/panel_prod_hard_deepswe_med_m28/secrets_scan.txt

@@ -1,17 +1,19 @@
 # secrets_scan — datasets/panel_prod_hard_deepswe_med_m28
-scanned_at: 2026-07-19
-wave: m28d
+scanned_at: 2026-07-20T12:02Z (m29c durable verify refresh)
+wave: m28d / m29c-verify
 tool: offline regex (OPENROUTER/sk-/gho_/ghp_/hf_/Bearer/GITHUB_TOKEN/HF_TOKEN/url-userinfo/oxylabs-userinfo)
 files_scanned:
   - SKIP_PREFLIGHT_NOTE.md
-  - scoreboard.json
+  - SUMMARY.md
+  - _free_after.txt
+  - _free_before.txt
+  - eval_run.log
   - ledger.jsonl
   - ledger_summary.json
   - report.json
-  - eval_run.log
-  - _free_before.txt
-  - _free_after.txt
-  - SUMMARY.md
+  - scoreboard.json
+  - secrets_scan.txt
 hit_count: 0
 result: CLEAN
 note: eval_run.pid excluded from scan/commit (runtime residue)
+note: m29c verified VAL-DCOV-007 from durable artifacts only; no pier re-eval