fix(providers): suppress stale reconnect replay

[TheGreatAxios]

Summary

• Deferred reconnect completion revalidates its recovery generation before replaying a failed turn
• A superseded reconnect callback cannot inject an old turn into a newer operator attempt
• Existing one-shot success, cancellation, failure, and committed-turn behavior remains unchanged

Verification

• bun run check passes
• Regression coverage advances the recovery generation before invoking the older successful completion callback

Follow-up to #1298

[TheGreatAxios]

Review · Fix verified

No findings. Deferred reconnect completion now revalidates generation ownership, suppressing stale callbacks while preserving current-generation exactly-once replay and cancellation, failure, and committed-turn behavior.

Verification: independent review is CLEAN; focused reconnect, submit, and exit suites pass; bun run check passes with 8,148 tests and 0 failures; all GitHub checks pass; git diff --check origin/main...HEAD passes.

[linear-code]

CL-9792