Retire WSGI evidence ingress fallbacks

[cbusillo]

Summary

• remove retired legacy WSGI evidence-ingress handlers for deployment, backup-gate, promotion, preview, runner-host hygiene, and runner-lane registration evidence
• make direct legacy WSGI calls to those evidence paths fail closed while native FastAPI routes remain authoritative
• update compatibility/service-boundary docs and replace duplicate WSGI evidence tests with a retirement assertion

Refs #1322

Validation

• uv run python -m unittest tests.test_service.LaunchplaneServiceTests.test_evidence_ingress_routes_are_retired_from_legacy_wsgi_app tests.test_http_app.FastApiDeploymentEvidenceStoreGateTests tests.test_http_app.FastApiBackupGateEvidenceStoreGateTests tests.test_http_app.FastApiPromotionEvidenceStoreGateTests tests.test_http_app.FastApiPreviewGenerationEvidenceStoreGateTests tests.test_http_app.FastApiPreviewDestroyedEvidenceStoreGateTests tests.test_http_app.FastApiRunnerHostHygieneAuditEvidenceStoreGateTests tests.test_http_app.FastApiRunnerLaneRegistrationAuditEvidenceStoreGateTests tests.test_http_app.FastApiDeploymentEvidenceTests tests.test_http_app.FastApiBackupGateEvidenceTests tests.test_http_app.FastApiPromotionEvidenceTests tests.test_http_app.FastApiPreviewGenerationEvidenceTests tests.test_http_app.FastApiPreviewDestroyedEvidenceTests tests.test_http_app.FastApiRunnerHostHygieneAuditEvidenceTests tests.test_http_app.FastApiRunnerLaneRegistrationAuditEvidenceTests
• uv run python -m unittest tests.test_service.LaunchplaneServiceTests
• uv run python -m unittest
• uv run --extra dev ruff check control_plane/service.py tests/test_service.py
• uv run --extra dev ruff check .
• uv run --extra dev ruff format --check control_plane/service.py tests/test_service.py
• uv run --extra dev mypy control_plane tests
• uv run /Users/cbusillo/Developer/codex-skills/jetbrains-inspection/scripts/jb-inspect.py closeout --repo "$PWD" --scope changed_files

Notes:

• uv run --extra dev ruff format --check . still reports existing unrelated repo-wide formatting drift across 56 files; changed Python files are formatted.
• Two review agents checked the diff; both were green, with only informational notes.