ci(deploy): mount postgres init as a DIRECTORY (fix 'Is a directory')

The single-file bind mount ./scripts/init-db.sh left a stale empty dir in the
reused act_runner workspace → mounted as a directory → migrations never ran →
empty schemas → backend 28P01/connection failures. Move the init script to
deploy/postgres-initdb/00-init.sh and mount the whole DIR at
/docker-entrypoint-initdb.d (robust, like the migrations dir). Deploy checkout
now 'git clean -ffd' to purge stale workspace dirs.

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

.gitea/workflows/ci-cd.yml

@@ -66,6 +66,9 @@ jobs:
           git config http.extraheader "Authorization: Bearer ${TOKEN}"
           git fetch --depth=1 origin "${REF}"
           git checkout -f FETCH_HEAD
+          # Remove stale Docker-created bind-mount dirs from a previous run (e.g. an
+          # empty scripts/init-db.sh dir) so they don't shadow real files. -e keeps .env.
+          git clean -ffd -e .env || true
 
       - name: Write .env (from ENV_FILE secret)
         run: printf '%s' "$ENV_FILE" > .env