feat(wbfy): strip retired push-back leftovers from test callers

[exKAZUu]

Customer Summary

• Repositories regenerated by wbfy no longer keep CI wiring that only served the retired automated-fix flows: the wbfy push-branch trigger and the statuses: write permission disappear from test workflow callers.
• No behavior change for day-to-day development; pull-request test runs are unaffected.

Technical Summary

• Removed wbfy from the on.push.branches of the test / test-rust caller templates in packages/wbfy/src/generators/workflow.ts, and filter the merged-in wbfy entry out of existing callers (alongside the existing renovate/** filter).
• Delete a merged-in permissions.statuses from test / test-rust callers; the existing empty-permissions cleanup in writeYaml drops the object when it empties.
• Added a unit test pinning that an existing caller with branches: [main, wbfy] and statuses: write regenerates without them.

Why

• The nightly self-applying wbfy caller pushed a branch named wbfy (hence the push trigger), and the reusable test workflow posted an aggregate commit status for autofix push-back dispatch runs (hence statuses: write). Both flows are retired (reusable-workflows#484/fix(deps): update all non-major dependencies #485, shared#1110/feat(wbfy)!: stop generating autofix.ci workflows and delete existing ones #1112), but wbfy's array-combining merge preserved these leftovers from older callers forever, so the fleet-wide wbfy run would never converge callers to the post-retirement shape.

Testing

• bun run vitest run test/unit in packages/wbfy (30 files / 307 tests passed, including the new case).
• bun verify at the repository root.

[gemini-code-assist]

Code Review

This pull request removes the retired wbfy push branch and statuses: write permissions from generated workflows, ensuring older configurations are cleaned up during regeneration. A corresponding unit test has been added to verify this behavior. No review comments were provided, so there is no feedback to address.