[Stella Huang (StellaHuang95)]

Summary

• enable PEP 723 inline-script support when VS Code applies the startup ExP default after extension activation, while keeping explicit setting changes reload-only
• register the inline manager, routing, diagnostics, commands, CodeLens, and restored-association work as one rollback-safe transaction
• harden manager-readiness handling for unregister/re-register and disposal races
• add deterministic real-VS-Code coverage for a delayed experiment default plus focused unit coverage for precedence, rollback, and in-flight metadata behavior

Validation

• lint passed
• TypeScript compilation passed
• full unit suite: 3,521 passing, 9 pending
• smoke hosts: 31 passing; explicit-on 1 passing; delayed-ExP 1 passing
• integration suite: 62 passing, 8 pending
• E2E suite: 4 passing
• full inline-manager unit suite: 364 passing
• manual workflow verified delayed enablement, setup CodeLens, environment creation, execution, identical-metadata cache reuse, dependency-change invalidation, and the plain-file control
• packaged build verified against the live private ExP treatment; logs confirmed late activation, inline-manager registration, and completed feature activation