fix: address project review findings

Security and robustness:
- storage-agent rejects an empty INTERNAL_TOKEN (config notEmpty + middleware)
- api takes the client IP only from X-Real-IP (chi RealIP trusted True-Client-IP)
- /readyz reports ok/fail and logs the cause; checks run in parallel with a timeout
- storage-agent shuts down gracefully; shared httpx.NewServer/Serve with IdleTimeout
- goose migrations take a Postgres advisory lock
- recommender readyz: per-check timeout, redis socket timeouts

Clients:
- Android release allows cleartext HTTP for LAN servers (expo-build-properties)
- checkServer times out after 10s; connect button is disabled while checking

Deploy and CI:
- install.sh hands cache/uploads/updates/models to the non-root service users
- update.sh refuses downgrades unless PIPU_ALLOW_DOWNGRADE=1
- recommender/analyzer get only the env they need; required secrets fail fast
- nginx security headers and CSP; strip True-Client-IP
- dev compose binds ports to 127.0.0.1; postgres/redis images pinned
- version.mjs fails on a malformed explicit tag instead of releasing 0.0.0-dev
- contract check catches untracked generated files
- final releases fail without a release keystore; changelog skips rc tags

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

services/api/internal/system/handler_test.go

@@ -20,7 +20,7 @@ func newServer(checks map[string]system.Checker) http.Handler {
 		Version:               "1.2.3",
 		SupportedLocales:      []string{"ru", "en"},
 		MinAndroidVersionCode: 10203,
-	}, checks)
+	}, nil, checks)
 	return server.NewRouter(server.Deps{System: h})
 }
 
@@ -68,7 +68,7 @@ func TestReadyz(t *testing.T) {
 
 		assert.Equal(t, http.StatusServiceUnavailable, rec.Code)
 		assert.Equal(t, "degraded", body["status"])
-		assert.Equal(t, map[string]any{"postgres": "ok", "redis": "connection refused"}, body["checks"])
+		assert.Equal(t, map[string]any{"postgres": "ok", "redis": "fail"}, body["checks"])
 	})
 }