fix(onboarding): targets visibility + unified pipeline by default

The onboarding wizard created OnboardedTargets that were invisible in the
dashboard, and triggering a scan failed with "Repository <id> not found":
`/targets/{id}/scan` went through `run_scan`, which consulted the global
`unified_pipeline` flag and fell to the legacy repository pipeline (reads
`repositories`, not `onboarded_targets`).

Agent
- Add `ComplianceAgent::run_target_scan`, always dispatching to the unified
  `run_target` pipeline. The target-scan endpoint operates on
  `onboarded_targets` by construction, so it must not depend on the
  transition flag. `trigger_target_scan` now calls it.
- Default `UNIFIED_PIPELINE` to on (no legacy `repositories` data in prod);
  set `UNIFIED_PIPELINE=0` to opt back to the legacy pipeline.
- Scheduler now scans `onboarded_targets` (via `run_target_scan`) instead of
  the legacy `repositories` collection.

Dashboard
- New Targets page (`/targets`): lists onboarded targets with detected type,
  artifacts, findings count, applicable-scans matrix (on expand), plus Run
  scan and Delete. Sidebar "Repositories" nav becomes "Targets".
- Remove the "Add Repository" form from the Repositories page — onboarding
  is the single entry point (private-repo auth + issue tracker move into the
  onboarding flow, revisable on the target).
- Add `delete_target` server fn.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

.gitea/workflows/ci.yml

@@ -29,10 +29,13 @@ env:
   CARGO_NET_RETRY: "10"
   CARGO_HTTP_MULTIPLEXING: "false"
 
-# Cancel in-progress runs for the same branch/PR
+# Cancel superseded PR runs, but NEVER cancel main-branch runs — those build and
+# deploy per-service images, and cancelling one merge's deploy when the next
+# merge lands leaves a service un-deployed (as happened between two back-to-back
+# merges). So cancel-in-progress only for pull_request events.
 concurrency:
   group: ${{ github.workflow }}-${{ github.ref }}
-  cancel-in-progress: true
+  cancel-in-progress: ${{ github.event_name == 'pull_request' }}
 
 jobs:
   # ---------------------------------------------------------------------------