chore(ci): restore bump schedule to 05:17 UTC

Revert the temporary 17:39 test time now that the manual run has been
kicked off; keep the daily cadence.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

docs/ROADMAP.md

@@ -1850,7 +1850,7 @@ Design/decision records and a running log of shipped work (items marked
   already eval/build/VM-tested and one hardware promotion away from `v1` —
   worth fast-laning lock-only/security bumps ahead of feature batches.
   **Shipped since:** `.gitea/workflows/check.yml` (eval tier on every main
-  push) and `bump.yml` (daily 17:39 UTC scheduled lock bump, eval + V1
+  push) and `bump.yml` (daily 05:17 UTC scheduled lock bump, eval + V1
   build gate, auto-lands on green — first landing 8fded63, 2026-07-06;
   cadence weekly→daily 2026-07-20).
   2026-07-12: both gates moved from one big `nix flake check --no-build`