Fix environment extension activation with scoped settings - #26117

🔒 Automated review in progress — Bill Schnurr (@bschnurr) is auto-reviewing this PR.

Verification: The relevant tests could not be fully run in the isolated environment; this review is not fully verified.

Result: could-not-verify

Summary: The PR adds two focused regression tests for scoped environment-extension activation. No tests could execute because the isolated container image is unavailable for `microsoft/vscode-python`, and local fallback was not authorized. Verification is therefore blocked by the environment.

Test runs: 1 not run

• ⚠️ Not run | Dependency and test discovery | git status --short && git diff --name-status upstream/main...HEAD && git diff --stat upstream/main...HEAD && if exist node_modules (echo NODE_MODULES_PRESENT) else (echo NODE_MODULES_MISSING)

Container verification could not start: no trusted sandbox image is configured for microsoft/vscode-python. Local execution was not authorized.

Verification: The relevant tests could not be fully run in the isolated environment; this review is not fully verified.

Result: could-not-verify

Summary: Verification could not run because no trusted sandbox image is configured for `microsoft/vscode-python`, and local execution was not authorized. The PR adds two focused unit tests covering conflicting scoped settings and the enabled path. No executable test result was obtained, so confidence is limited.

Test runs: 1 not run

• ⚠️ Not run | Verification preflight and test discovery | git status --short && git diff --name-status upstream/main...HEAD && git diff --stat upstream/main...HEAD && node -e "const p=require('./package.json'); console.log(JSON.stringify({scripts:p.scripts},null,2))" && if [ -d node_modules ]; then echo NODE_MODULES_PRESENT; else echo NODE_MODULES_MISSING; fi

Container verification could not start: no trusted sandbox image is configured for microsoft/vscode-python. Local execution was not authorized for this PR HEAD.