ci: split workflows for linear development flow

Reshapes .gitea/workflows/ around the new main ← development ←
feature/* branching model:

- go-unit.yaml — Go unit tests, runs on push/PR matching Go paths
- ui-test.yaml — narrowed to Vitest + Playwright only (Go tests now
  live in go-unit.yaml)
- integration.yaml — testcontainers suite, fires on PR to
  development/main and on push to development
- dev-deploy.yaml — builds the stack and (re)deploys tools/dev-deploy/
  on every merge into development
- prod-build.yaml — builds prod images on push to main and uploads
  docker save bundles as artifacts (30-day retention)
- deploy-prod.yaml — workflow_dispatch placeholder for the future
  SSH-based rollout

ui-release.yaml is removed; its v* tag trigger is superseded by
prod-build.yaml plus the manual deploy-prod entry point.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

.gitea/workflows/deploy-prod.yaml

@@ -0,0 +1,31 @@
+name: deploy-prod
+
+# Placeholder for the production rollout workflow. Today it only proves
+# the manual entry point works; the actual `docker save | ssh prod
+# docker load` + remote `docker compose up -d` pipeline is wired in
+# once the production host, SSH credentials, and DNS are decided.
+
+on:
+  workflow_dispatch:
+    inputs:
+      image_tag:
+        description: "Image tag to deploy (commit-<sha12>, produced by prod-build.yaml)"
+        required: true
+        type: string
+
+jobs:
+  deploy:
+    runs-on: ubuntu-latest
+    defaults:
+      run:
+        shell: bash
+    steps:
+      - name: Announce target
+        run: |
+          echo "Would deploy image tag: ${{ inputs.image_tag }}"
+          echo "TODO:"
+          echo "  1. Download galaxy-images-${{ inputs.image_tag }} from prod-build artifacts."
+          echo "  2. scp the .tar.gz bundles to the production host."
+          echo "  3. ssh prod 'docker load -i ...' for backend / gateway / engine."
+          echo "  4. ssh prod 'docker compose -f /opt/galaxy/docker-compose.yml up -d'."
+          echo "  5. Probe https://api.galaxy.com/healthz and roll back on failure."