Add bounded final-size recovery probe

[cbusillo]

Summary

• add one deterministic measured directional probe when a real final-size miss has no usable calibrated candidate or bracket
• require compatible finite quality, unchanged final-size band, source cap, CRF bounds, and the existing single full-output retry budget
• keep malformed, incompatible, exhausted, and non-monotonic evidence fail closed
• reproduce the Bluey and NewsRadio stored traces in unit and production-path tests

Validation

• bash scripts/pre-commit-check.sh — 1,643 passed, 2 skipped; CLI, frontend checks/lint/tests/build, and web-route smoke passed
• scoped Ruff passed
• git diff --check passed
• PyCharm routed to the exact worktree; final closeout remained inconclusive because the IDE returned stale results after its internal retry

Runtime scope

No media was executed or promoted by this change. A controlled exact-item verification remains a separate post-merge step.

Refs #439
Refs #256
Refs #273