re-trial on transient execution result mismatch

[AdoAdoAdo]

Reasoning behind the pull request

Proposed changes

Testing procedure

Pre-requisites

Based on the Contributing Guidelines the PR author and the reviewers must check the following requirements are met:

• was the PR targeted to the correct branch?
• if this is a larger feature that probably needs more than one PR, is there a feat branch created?
• if this is a feat branch merging, do all satellite projects have a proper tag inside go.mod?

[Copilot]

Pull request overview

This PR adds an automatic recovery path for shard bootstrap syncing when a transient ErrExecutionResultDoesNotMatch occurs, by rewinding local pending execution results and triggering re-execution, with a per-nonce cooldown to prevent repeated rewinds.

Changes:

• Add recovery logic in baseBootstrap.doJobOnSyncBlockFail() to handle execution-result mismatches by removing pending results from the first diverging nonce (or from last notarized + 1).
• Track recovery attempts per nonce with a cooldown window, and clean up attempt-tracking data behind the final block nonce.
• Add a comprehensive shard bootstrap test suite covering mismatch scenarios, fallbacks, cooldown behavior, and failure modes, plus test-only accessors.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

File	Description
process/sync/baseSync.go	Adds mismatch-recovery logic with per-nonce cooldown tracking and cleanup.
process/sync/shardblock_test.go	Adds tests validating recovery triggering, rewind selection, fallback behavior, and cooldown semantics.
process/sync/export_test.go	Exposes test-only helpers to observe/adjust preparedForSync, cooldown, and recovery-attempt counters.

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[codecov]

Codecov Report

❌ Patch coverage is 90.78947% with 7 lines in your changes missing coverage. Please review.
✅ Project coverage is 77.69%. Comparing base (2539513) to head (6bc12b1).

Files with missing lines	Patch %	Lines
process/sync/baseSync.go	90.78%	4 Missing and 3 partials ⚠️

Additional details and impacted files

@@                 Coverage Diff                 @@
##           feat/testnet-fixes    #7901   +/-   ##
===================================================
  Coverage               77.68%   77.69%           
===================================================
  Files                     885      885           
  Lines                  125828   125904   +76     
===================================================
+ Hits                    97745    97816   +71     
- Misses                  21603    21608    +5     
  Partials                 6480     6480           

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