feat(git-sync): GitSyncModule orchestrator + config + listener (Phase A.4b/B)

Control plane wiring (plan §5-§11):
- PageService create/update/movePage now honor provenance actor 'git-sync'
  (stamp lastUpdatedSource='git-sync'), closing the A.4a gap.
- EnvironmentService: GIT_SYNC_ENABLED / DATA_DIR / REMOTE_TEMPLATE /
  POLL_INTERVAL_MS / DEBOUNCE_MS / SERVICE_USER_ID (required-if-enabled) /
  SSH_KEY_PATH + validation.
- VaultRegistryService: per-space vault path + cached VaultGit.
- GitSyncOrchestrator: per-space Redis leader-lock (SET NX PX + CAS-Lua release,
  randomUUID instanceId) + in-process mutex; runOnce drives the vendored engine
  PULL (readExisting->computePullActions->applyPullActions) then PUSH (runPush)
  with the bound native GitSyncClient + VaultGit; @Interval poll-safety gated on
  GIT_SYNC_ENABLED; imports plain ScheduleModule (TelemetryModule owns forRoot).
- PageChangeListener: @OnEvent PAGE_* -> per-space debounce -> runOnce, with a
  best-effort lastUpdatedSource==='git-sync' loop-guard.
- GitSyncController: admin POST /api/git-sync/trigger + GET /status (ops/e2e).
- GitSyncModule registered in app.module. Enabled-space enumeration uses
  settings.gitSync.enabled, falling back to all live spaces until Phase C writes
  the flag (master gate = GIT_SYNC_ENABLED).

tsc clean; 713 tests/71 suites pass; dev server hot-reloaded the module (route
live, DI graph boots). Live pull/push round-trip verified next.

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

apps/server/src/integrations/environment/environment.service.ts

@@ -320,4 +320,58 @@ export class EnvironmentService {
       .map((o) => o.trim())
       .filter(Boolean);
   }
+
+  // --- git-sync (plan §7.2) -------------------------------------------------
+
+  /** Global master switch for the git-sync control plane (default false). */
+  isGitSyncEnabled(): boolean {
+    return (
+      this.configService.get<string>('GIT_SYNC_ENABLED', 'false').toLowerCase() ===
+      'true'
+    );
+  }
+
+  /**
+   * Root directory holding the per-space vault repos. Defaults to
+   * `<DATA_DIR or ./data>/git-sync`. `DATA_DIR` is read directly (no dedicated
+   * getter exists in this codebase) so the vault root tracks the data volume.
+   */
+  getGitSyncDataDir(): string {
+    const explicit = this.configService.get<string>('GIT_SYNC_DATA_DIR');
+    if (explicit) return explicit;
+    const dataDir = this.configService.get<string>('DATA_DIR') || './data';
+    return `${dataDir.replace(/\/+$/, '')}/git-sync`;
+  }
+
+  /** Optional remote template, e.g. `git@host:vault-{spaceId}.git`. */
+  getGitSyncRemoteTemplate(): string | undefined {
+    return this.configService.get<string>('GIT_SYNC_REMOTE_TEMPLATE');
+  }
+
+  /** Poll-safety interval in ms (default 15000). */
+  getGitSyncPollIntervalMs(): number {
+    return parseInt(
+      this.configService.get<string>('GIT_SYNC_POLL_INTERVAL_MS', '15000'),
+    );
+  }
+
+  /** Event debounce window in ms (default 2000). */
+  getGitSyncDebounceMs(): number {
+    return parseInt(
+      this.configService.get<string>('GIT_SYNC_DEBOUNCE_MS', '2000'),
+    );
+  }
+
+  /**
+   * The service user id git-sync writes are attributed to. Required when sync is
+   * enabled (validated in environment.validation.ts); optional otherwise.
+   */
+  getGitSyncServiceUserId(): string | undefined {
+    return this.configService.get<string>('GIT_SYNC_SERVICE_USER_ID');
+  }
+
+  /** Optional path to the SSH key used for git remote access. */
+  getGitSyncSshKeyPath(): string | undefined {
+    return this.configService.get<string>('GIT_SYNC_SSH_KEY_PATH');
+  }
 }