Intent of codexForkPlan.ts ×3

All 4 exact tests in this concept. Every test is marked by where it enters the hierarchy.

mocha:v1|namespace=vscode@05c208e9e28d8c1c723fa08f85e2b7a96092e8e5|file=vs/ 4 tests
- platform/ 4 tests
  - agentHost/ 4 tests
    
    test/ 4 tests
    
    node/ 4 tests
    
    codex/ 4 tests
    
    codexForkPlan.test|title=codexForkPlan resolveForkBoundary locates the boundary by codex turn id (first / 1 test
    
    middle / 1 test
    
    mocha:v1|namespace=vscode@05c208e9e28d8c1c723fa08f85e2b7a96092e8e5|file=vs/platform/agentHost/test/node/codex/codexForkPlan.test|title=codexForkPlan resolveForkBoundary locates the boundary by codex turn id (first / middle / last)|occurrence=1 Introduced here
    
    mocha:v1|namespace=vscode@05c208e9e28d8c1c723fa08f85e2b7a96092e8e5|file=vs/platform/agentHost/test/node/codex/codexForkPlan.test|title=codexForkPlan resolveForkBoundary falls back to turnIndex when the id is not found|occurrence=1 Inherited codexForkPlan.ts ×1
    
    mocha:v1|namespace=vscode@05c208e9e28d8c1c723fa08f85e2b7a96092e8e5|file=vs/platform/agentHost/test/node/codex/codexForkPlan.test|title=codexForkPlan resolveForkBoundary rejects an unresolvable boundary instead of keeping full history|occurrence=1 Inherited codexForkPlan.ts ×1
    
    mocha:v1|namespace=vscode@05c208e9e28d8c1c723fa08f85e2b7a96092e8e5|file=vs/platform/agentHost/test/node/codex/codexForkPlan.test|title=codexForkPlan resolveForkBoundary treats an empty source thread as a valid empty fork|occurrence=1 Inherited codexForkPlan.ts ×1