test(git-sync): add reviewer-requested coverage across engine, server, client

Implements the test cases called out in the PR #119 review threads
(code-review, test-strategy report, red-team) — TESTS ONLY, no production
code changes.

packages/git-sync (vitest):
- lib converter/markdown gaps: pageBreak data-loss (it.fails repro),
  subpages lossy round-trip, nested/fenced callouts, ol->taskList bridge,
  column.width number<->string drift, empty details.
- engine units: parentFolderFile, planReconciliation swap/chained move,
  buildVaultLayout last-resort-by-id, firstDivergence, applyPushActions /
  applyPullActions failure isolation.
- real temp-git integration: diffNameStatus -z rename+add/modify
  alignment, copy-line behavior, per-invocation committer identity (no
  leak into repo/global config).
- ENFORCED type-level GitSyncClient contract via vitest typecheck over a
  *.test-d.ts file (tsconfig.vitest.json; build tsconfig untouched).

apps/server (jest):
- orchestrator: delete-cap neutralization + fail-safe, Redis lock / mutex
  skip ladder + release-on-throw, merge guard, pull/push order, remote
  template substitution, poll lifecycle.
- page-change listener: loop-guard, debounce coalescing, id resolution,
  error swallowing.
- vault registry, controller authz (trigger + status), env
  validation/getters, page.service git-sync provenance stamping,
  persistence precedence (agent > git-sync > user) + no boundary snapshot,
  space.service audit-delta, space.repo jsonb-merge, converter-gate corpus
  extension (mention/math/details/marks).

apps/client (vitest + testing-library):
- history-item git-sync badge: render gating + non-clickable.
- edit-space-form toggle: initial state, optimistic payload, rollback on
  error, disabled states.

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

apps/server/src/integrations/environment/environment.validation.spec.ts

@@ -0,0 +1,74 @@
+import { plainToInstance } from 'class-transformer';
+import { validateSync } from 'class-validator';
+import { EnvironmentVariables } from './environment.validation';
+
+/**
+ * Validation-layer coverage for the git-sync env contract (test-strategy Module
+ * 4 / item #4). We drive the decorated class with `validateSync` directly — the
+ * exported `validate()` helper calls `process.exit(1)` on failure and so cannot
+ * be asserted in-process. We only assert the git-sync rules, providing the
+ * minimal always-required fields so unrelated validators do not add noise.
+ */
+describe('EnvironmentVariables — git-sync validation', () => {
+  // A baseline config that satisfies the unconditionally-required fields
+  // (DATABASE_URL, REDIS_URL, APP_SECRET) so the only errors we ever see come
+  // from the git-sync rules under test.
+  const baseConfig = {
+    DATABASE_URL: 'postgres://user:pass@localhost:5432/docmost',
+    REDIS_URL: 'redis://localhost:6379',
+    APP_SECRET: 'x'.repeat(32),
+  };
+
+  const validate = (extra: Record<string, unknown>) => {
+    const instance = plainToInstance(EnvironmentVariables, {
+      ...baseConfig,
+      ...extra,
+    });
+    return validateSync(instance);
+  };
+
+  const errorFor = (errors: ReturnType<typeof validateSync>, property: string) =>
+    errors.find((e) => e.property === property);
+
+  it('flags GIT_SYNC_SERVICE_USER_ID when GIT_SYNC_ENABLED="true" and the id is absent', () => {
+    const errors = validate({ GIT_SYNC_ENABLED: 'true' });
+
+    const err = errorFor(errors, 'GIT_SYNC_SERVICE_USER_ID');
+    expect(err).toBeDefined();
+    // @IsNotEmpty is the failing constraint (sync is on but no attributable
+    // author was configured).
+    expect(err?.constraints).toHaveProperty('isNotEmpty');
+  });
+
+  it('accepts GIT_SYNC_ENABLED="true" once GIT_SYNC_SERVICE_USER_ID is present', () => {
+    const errors = validate({
+      GIT_SYNC_ENABLED: 'true',
+      GIT_SYNC_SERVICE_USER_ID: 'service-user-1',
+    });
+
+    expect(errorFor(errors, 'GIT_SYNC_SERVICE_USER_ID')).toBeUndefined();
+  });
+
+  it('does not require the service user id when git-sync is disabled (unset)', () => {
+    const errors = validate({});
+
+    // The @ValidateIf gate (GIT_SYNC_ENABLED === "true") is not met, so the
+    // required-if-enabled rule is skipped entirely.
+    expect(errorFor(errors, 'GIT_SYNC_SERVICE_USER_ID')).toBeUndefined();
+  });
+
+  it('does not require the service user id when git-sync is explicitly "false"', () => {
+    const errors = validate({ GIT_SYNC_ENABLED: 'false' });
+
+    expect(errorFor(errors, 'GIT_SYNC_SERVICE_USER_ID')).toBeUndefined();
+    expect(errorFor(errors, 'GIT_SYNC_ENABLED')).toBeUndefined();
+  });
+
+  it('rejects a GIT_SYNC_ENABLED value outside the {true,false} set via @IsIn', () => {
+    const errors = validate({ GIT_SYNC_ENABLED: 'maybe' });
+
+    const err = errorFor(errors, 'GIT_SYNC_ENABLED');
+    expect(err).toBeDefined();
+    expect(err?.constraints).toHaveProperty('isIn');
+  });
+});