feat: image version identity + DB-config parity for nightly scripts

Version: CI now tags images YYYY.MM.DD-<shortsha> alongside :latest/:sha
and passes GIT_SHA/BUILD_TAG build-args; the running app reports them via
dashboard /api/health and admin /api/status (TrueNAS custom apps only show
'custom/1.0.0', so the app self-reports what it actually runs).

Config parity: every scheduler-run script (nightly_tune, eod_replay,
premarket_eval, regime, market_context, experiments cli) now loads
config_overrides at startup like the live services do — a bare env would
replay under DEFAULT exits (the documented 4.5x-baseline landmine).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

.github/workflows/docker.yml

@@ -64,12 +64,19 @@ jobs:
         with:
           username: ${{ secrets.DOCKERHUB_USERNAME }}
           password: ${{ secrets.DOCKERHUB_TOKEN }}
+      - id: ver
+        run: echo "tag=$(date -u +%Y.%m.%d)-${GITHUB_SHA::7}" >> "$GITHUB_OUTPUT"
       - uses: docker/build-push-action@v6
         with:
           context: .
           push: true
+          build-args: |
+            GIT_SHA=${{ github.sha }}
+            BUILD_TAG=${{ steps.ver.outputs.tag }}
           tags: |
             ghcr.io/fez5587/momentum-app:latest
             ghcr.io/fez5587/momentum-app:${{ github.sha }}
+            ghcr.io/fez5587/momentum-app:${{ steps.ver.outputs.tag }}
             fez5587/momentum-app:latest
             fez5587/momentum-app:${{ github.sha }}
+            fez5587/momentum-app:${{ steps.ver.outputs.tag }}