fix addressed registry recovery blockers

backend/src/workspaces/git-repository.ts

@@ -132,6 +132,11 @@ export class GitWorkspaceRepository {
   private validateRevision(revision: string): void {
     if (!/^[0-9a-f]{40}$/.test(revision)) throw new WorkspaceRegistryError("workspace_invalid", "Workspace revision is invalid");
   }
+  async parentOf(revision: string): Promise<string | undefined> {
+    this.validateRevision(revision);
+    return (await this.gitOptional(["rev-parse", `${revision}^`]))?.trim();
+  }
+
   async workspacePathsAt(revision: string): Promise<string[]> {
     this.validateRevision(revision);
     const output = await this.git(["ls-tree", "-r", "--name-only", revision, "--", "workspaces"]);
@@ -221,6 +226,24 @@ export class GitWorkspaceRepository {
     await rm(join(this.repoPath, path), { force: true });
   }
 
+  /** Push an already-created commit by its exact object ID. Repeating this is idempotent. */
+  async pushExact(revision: string): Promise<void> {
+    this.validateRevision(revision);
+    try {
+      await this.git(["push", "origin", `${revision}:refs/heads/${this.config.branch}`]);
+    } catch (error) {
+      throw this.sanitizeGitError(error);
+    }
+  }
+
+  /** Create a local publication commit without contacting the remote. */
+  async commitOnly(paths: readonly string[], message: string): Promise<GitStatus> {
+    if (paths.length === 0 || paths.some((path) => !this.isRegistryArtifactPath(path))) throw new WorkspaceRegistryError("workspace_invalid", "Workspace repository path is invalid");
+    await this.git(["add", "--", ...paths]);
+    await this.git(["commit", "-m", message], this.publicationIdentity());
+    return await this.status();
+  }
+
   /** Commit and push a fixed set of validated artifact paths without exposing Git output. */
   async commitAndPush(paths: readonly string[], message: string): Promise<GitStatus> {
     if (paths.length === 0 || paths.some((path) => !this.isRegistryArtifactPath(path))) {