L1 CI: traceability check should accept Refs/Updates/Resolves verbs

[gHashTag]

Problem

The L1 TRACEABILITY workflow (.github/workflows/l1-traceability.yml) only accepts Closes/Fixes #N but rejects Refs #N and Updates #N, which are standard GitHub linking verbs for incremental progress on the same epic issue.

Impact

PR #593 (the 3-month FGG676 SPI-flash unblock) has 8 commits using Refs #592 / Updates #592 as progress markers — they fail L1 even though they reference issue #592 correctly. This blocks merge of silicon-verified work.

Proposed fix

Accept the full canonical set:

• Close(s) / Fix(es) / Resolve(s) — closes on merge
• Ref(s) — references (work in progress)
• Update(s) — progress update on existing issue

Fix in PR #605.