feat(cli,ci): admin reset-password + migrate subcommands; test-DB isolation + CI integration job

#321 — `minstrel admin reset-password [-user admin] [-password X]`:
loads config, updates BOTH password_hash (bcrypt) and subsonic_password
(plaintext, for Subsonic t+s) so neither auth path is left stale;
generates+prints a strong password when -password is omitted. Recovers
a locked-out operator without DB surgery. Subcommand dispatch added to
main.go (os.Args switch before flag-parse; server path untouched) plus
a `minstrel migrate` subcommand exposing db.Migrate standalone.

#339 — integration tests no longer truncate the dev DB:
- deploy/initdb creates minstrel_test on a fresh compose volume;
  `make test-integration` ensures it idempotently and points
  MINSTREL_TEST_DATABASE_URL at minstrel_test.
- docker-compose.yml + README updated.

CI integration job (test-go.yml): the prior workflow only ran
`go test -short -race` with no DB, so the entire integration suite
silently t.Skip'd — "CI green" never covered API/db/scanner. New
`integration` job runs the full `go test -race` against an ephemeral
Postgres service, using the act_runner shared-daemon pattern: no
published ports, discover the service container by job-name filter via
the docker socket, reach it by bridge IP, hard exactly-one assertion +
dev-compose-name reject (a wrong target would truncate real data),
TCP-wait, `minstrel migrate`, then test. Fast `test` job kept as the
quick gate.

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

.forgejo/workflows/test-go.yml

@@ -4,8 +4,16 @@ name: test-go
 # dev/main and PRs to main, scoped to Go-side files only — web-only or
 # Flutter-only diffs don't trigger this workflow.
 #
-# Integration tests needing Postgres/ffmpeg run locally via docker-compose;
-# they should guard with testing.Short() so this short-mode run skips them.
+# Two jobs: `test` (fast — vet + lint + `go test -short -race`, no DB) and
+# `integration` (full `go test -race` against an ephemeral Postgres).
+#
+# Integration-job DB wiring follows the act_runner shared-daemon pattern:
+# the runner's Docker daemon also runs the operator's dev compose stack,
+# so service containers get NO published ports (collision) and no
+# service-name DNS. We discover the service container by the job-scoped
+# name filter via the mounted docker socket and reach it by bridge IP.
+# The exactly-one assertion is a hard guard — pointing tests at the dev
+# Postgres would truncate it (the disaster Fable #339 exists to prevent).
 #
 # `web/build/` has a committed placeholder index.html so go:embed succeeds
 # without needing the SPA to be freshly built. Real builds happen in
@@ -54,3 +62,48 @@ jobs:
 
       - name: go test (short, race)
         run: go test -short -race ./...
+
+  integration:
+    runs-on: go-ci
+    services:
+      postgres:
+        image: postgres:16-alpine
+        env:
+          POSTGRES_USER: minstrel
+          POSTGRES_PASSWORD: minstrel
+          POSTGRES_DB: minstrel_test
+        # No `ports:` — the runner shares the operator's dev compose
+        # Docker daemon; publishing a fixed host port collides.
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Integration suite (discover service by bridge IP, migrate, test)
+        run: |
+          set -eux
+          # Discover THIS job's Postgres service container via the
+          # mounted docker socket. Scope by the job-name filter so the
+          # operator's dev compose `minstrel-postgres-*` (same image,
+          # same daemon) can never match. Require exactly one — abort
+          # loudly otherwise; a wrong target would truncate real data.
+          PG_LIST=$(docker ps --filter "name=integration" --filter "ancestor=postgres:16-alpine" --format '{{.ID}} {{.Names}}')
+          echo "candidates: ${PG_LIST:-<none>}"
+          PG_COUNT=$(printf '%s\n' "$PG_LIST" | grep -c . || true)
+          test "$PG_COUNT" = "1" || { echo "FATAL: expected exactly 1 postgres service container, got $PG_COUNT"; exit 1; }
+          PG_ID=$(printf '%s' "$PG_LIST" | awk '{print $1}')
+          PG_NAME=$(printf '%s' "$PG_LIST" | awk '{print $2}')
+          case "$PG_NAME" in
+            *minstrel-postgres*|*_postgres_*) echo "FATAL: matched the dev compose container ($PG_NAME), refusing"; exit 1 ;;
+          esac
+          PG_IP=$(docker inspect -f '{{range .NetworkSettings.Networks}}{{.IPAddress}}{{end}}' "$PG_ID")
+          test -n "$PG_IP"
+          export MINSTREL_TEST_DATABASE_URL="postgres://minstrel:minstrel@${PG_IP}:5432/minstrel_test?sslmode=disable"
+
+          # Wait for Postgres to accept TCP (no health-check dependency).
+          for i in $(seq 1 60); do (echo > "/dev/tcp/${PG_IP}/5432") 2>/dev/null && break; sleep 2; done
+
+          # Apply embedded migrations to the fresh test DB, then run the
+          # full suite (no -short → integration tests execute).
+          MINSTREL_DATABASE_URL="$MINSTREL_TEST_DATABASE_URL" go run ./cmd/minstrel migrate
+          go test -race ./...