Task 1.8 — Gitea CI dry-run workflow

.gitea/workflows/build.yml builds the directus image on path-filtered
pushes to main and validates the boot pipeline against a throwaway
Postgres before pushing the image to the registry. The dry-run is the
gate that catches snapshot drift, broken db-init scripts, or
incompatible schema changes before they reach stage.

Workflow shape (mirrors processor's CI but tailored to Directus):
- Path filter: snapshots/, db-init/, extensions/, scripts/,
  entrypoint.sh, Dockerfile, the workflow file itself.
  Docs-only commits (.planning/, README.md, compose.dev.yaml,
  package.json) do NOT trigger CI.
- Throwaway Postgres via services: block, pinned to the same
  timescale/timescaledb-ha:pg16.6-ts2.17.2-all tag as compose.dev.yaml.
- Plain `docker build` (NOT build-push-action) so the image stays in
  the local daemon for the subsequent docker run dry-run.
- Dry-run: --network host + --entrypoint bash to override the upstream
  entrypoint and run only apply-db-init.sh && schema-apply.sh.
  Skips bootstrap and pm2-runtime — the schema apply is the gate.
- Two image tags: :main (mutable) and :<sha> (immutable).
- Optional Portainer webhook gated on secret presence; curl -fsS so a
  misconfigured URL fails the step explicitly.

Spec corrections folded in (the spec's draft had two contradictions
that would have failed at runtime):
1. DB_HOST=localhost (not 'postgres'). With --network host, service
   containers are reachable on the runner's loopback by their port
   mapping, NOT by service name. Service-name resolution requires the
   default bridge network; --network host overrides it.
2. health-retries 20 (not 10). timescaledb-ha:*-all does more init
   work at boot than vanilla postgres; 50s isn't always enough.

Operator action required in the Gitea repo Settings before first run:
configure REGISTRY_USERNAME and REGISTRY_PASSWORD secrets (required for
push); optionally PORTAINER_WEBHOOK_URL (for auto-deploy).

Live verification deferred to first relevant commit. Documented in the
task spec's Done section: positive (clean snapshot → push succeeds)
and negative (malformed snapshot → halt before push) cases to validate
once CI runs.

ROADMAP marks 1.8 done. Phase 1 progress: 8/9 tasks complete (1.1–1.8);
only 1.9 (Rally Albania 2026 dogfood seed) remains before Phase 1 ships.

.planning/ROADMAP.md

@@ -42,7 +42,7 @@ These rules govern every task. Any deviation must be discussed and documented as
 
 ### Phase 1 — Slice 1 schema + deploy pipeline
 
-**Status:** 🟨 In progress (1.1–1.7 done; 1.8, 1.9 remaining)
+**Status:** 🟨 In progress (1.1–1.8 done; 1.9 remaining)
 **Outcome:** A Directus instance with the org-level catalog (orgs, users, organization_users, vehicles, devices and their org junctions) and event-participation collections (events, classes, entries, entry_crew, entry_devices) live and snapshot-tracked. `db-init/` covers the TimescaleDB extension, the `positions` hypertable, and the `faulty` column. Image builds via Gitea Actions with a CI dry-run that catches snapshot drift before deploy. Rally Albania 2026 is registered as the first event in admin UI to dogfood the registration workflow. **This is what Rally Albania 2026 needs.**
 
 [**See `phase-1-slice-1-schema/README.md`**](./phase-1-slice-1-schema/README.md)
@@ -56,7 +56,7 @@ These rules govern every task. Any deviation must be discussed and documented as
 | 1.5 | [Event-participation collections](./phase-1-slice-1-schema/05-event-participation-collections.md) | 🟩 | pending user commit |
 | 1.6 | [Schema snapshot/apply tooling](./phase-1-slice-1-schema/06-snapshot-tooling.md) | 🟩 | pending user commit |
 | 1.7 | [Image build & entrypoint](./phase-1-slice-1-schema/07-image-and-dockerfile.md) | 🟩 | pending user commit |
-| 1.8 | [Gitea CI dry-run workflow](./phase-1-slice-1-schema/08-gitea-ci-dryrun.md) | ⬜ | — |
+| 1.8 | [Gitea CI dry-run workflow](./phase-1-slice-1-schema/08-gitea-ci-dryrun.md) | 🟩 | pending user commit |
 | 1.9 | [Rally Albania 2026 dogfood seed](./phase-1-slice-1-schema/09-rally-albania-2026-seed.md) | ⬜ | — |
 
 ### Phase 2 — Course definition