[adamtheturtle]

Upgrade Pyrefly to 1.4.0 and initialize status, body, and headers in both validator-error base constructors. All 47 concrete error classes now supply complete response data to their base constructor, removing the uninitialized-field suppressions. Add regression tests for complete base-error responses and include them in the CI matrix.

Keep the 94 live-test matrix patterns on distinct credential slots below index 100, and append the new mock-only regression job after the existing patterns. This prevents credential wrapping from assigning a live job another job’s database.

Validation:

• 27 focused tests passed; 8 live-backend cases were skipped.
• Compared all 47 concrete errors before and after the refactor with fixed timestamps and UUIDs: status, body, headers, and exception arguments match.
• Pre-commit and full pre-push checks passed.
• The test partition check and workflow lint pass; all 94 live patterns have unique credential slots.
• No new type-checker suppressions or casts.