test(candidate-execution): use protected trace writes in fixtures

[drewstone]

Candidate execution fixtures wrote raw trace IDs directly to storage.
When an ID matched a redaction rule, finalization could not find the protected record.
This caused the single failure in main CI.

Use the supplied trace store for all 19 affected fixture writes.
Force a sensitive-looking ID in the receipt test and inspect the stored identity when checking redaction.
Production code and credential protection are unchanged.

Validation:

• A fixed sensitive-looking ID reproduced the same failure before the repair.
• All 30 execution and redaction tests passed after the repair.
• Biome, the version check, and commit hooks passed.
• PR CI and merged main CI passed all four jobs.
• Both Ubuntu runs passed 3,564 tests with six conditional skips, across 281 passing and two skipped files.
• Merged commit e28a6b64c0a3f09ee6463f4f5e4e79d6938cc56c has the exact reviewed tree.