Move Dokploy inspect read to FastAPI

[cbusillo]

Summary

• Move GET /v1/dokploy-targets/inspect from the legacy WSGI read dispatcher to native FastAPI.
• Delete the retired WSGI inspect matcher/handler path while keeping Dokploy target setup on the retained fallback.
• Add FastAPI route coverage for success, authz denial, DB-only storage requirement, invalid query mode, missing target, OpenAPI contract, and fallback precedence.
• Update service-boundary and compatibility-retirement docs for the native route ownership.

Validation

• uv run python -m unittest tests.test_http_app.FastApiDokployTargetInspectReadTests tests.test_service.LaunchplaneServiceTests.test_dokploy_target_inspect_read_is_retired_from_legacy_wsgi_app
• uv run --extra dev ruff check control_plane/http_app.py control_plane/service.py tests/test_http_app.py tests/test_service.py docs/compatibility-retirement.md docs/service-boundary.md
• uv run --extra dev ruff format --check control_plane/http_app.py control_plane/service.py tests/test_http_app.py tests/test_service.py
• git diff --check
• uv run --extra dev ruff check .
• uv run --extra dev mypy control_plane tests
• uv run python -m unittest (2748 tests)
• JetBrains changed-files inspection: clean
• Review agents: 2 green, no blockers