Execute and confirm an end-to-end dry-run release to an internal/alpha track

Part of #626

Why

This is the final validation step for #626: once the health declaration gate, the versionCode regression risk, and the credential/signing-key audit are resolved, the pipeline still needs to be proven end-to-end with an actual run, not just inspected.

Scope

Trigger a real release through the pipeline (either pre-release-upload.yml via a merge to main, or a controlled ps-release.yml tag push) targeting an internal/alpha track, and confirm it completes successfully from build through Play Store commit.

Acceptance Criteria

• A release run completes with the Upload to Play Store step succeeding (edit committed, not just artifact uploaded)
• Resulting build is visible on the target track in Play Console with the expected versionCode/versionName
• Any residual failure found during this run is filed as a new issue rather than patched ad hoc mid-ticket

Out of Scope

• Promoting the dry-run build to production
• Re-auditing credentials/signing or re-deriving the versionCode scheme — those are prerequisites tracked separately under #626

Links

• None