Simplify workspace creation with inline worktree API

Replace the multi-step new-agent route flow with a single
create_paseo_worktree endpoint that registers the workspace immediately
and creates the git worktree in the background. The sidebar now calls
this endpoint directly and shows a creating spinner inline.

Also auto-resolves the base branch from origin/HEAD when not explicitly
provided, removes the unused Tauri WebSocket transport layer, and
normalizes loopback endpoints to localhost.

Closes #125

packages/server/src/utils/checkout-git.test.ts

@@ -17,6 +17,7 @@ import {
   MergeFromBaseConflictError,
   NotGitRepoError,
   pushCurrentBranch,
+  resolveRepositoryDefaultBranch,
 } from "./checkout-git.js";
 import { createWorktree } from "./worktree.js";
 import { getPaseoWorktreeMetadataPath } from "./worktree-metadata.js";
@@ -707,6 +708,17 @@ describe("checkout git utilities", () => {
     expect(baseDiff.diff).not.toContain("file.txt");
   });
 
+  it("resolves the repository default branch from origin HEAD", async () => {
+    execSync("git checkout -b develop", { cwd: repoDir });
+    execSync("git checkout main", { cwd: repoDir });
+    execSync("git remote add origin https://github.com/acme/repo.git", { cwd: repoDir });
+    execSync("git update-ref refs/remotes/origin/main refs/heads/main", { cwd: repoDir });
+    execSync("git update-ref refs/remotes/origin/develop refs/heads/develop", { cwd: repoDir });
+    execSync("git symbolic-ref refs/remotes/origin/HEAD refs/remotes/origin/main", { cwd: repoDir });
+
+    await expect(resolveRepositoryDefaultBranch(repoDir)).resolves.toBe("main");
+  });
+
   it("merges to stored baseRefName when baseRef is not provided", async () => {
     // Create a non-default base branch with a unique commit.
     execSync("git checkout -b develop", { cwd: repoDir });

packages/server/src/utils/checkout-git.ts

@@ -708,7 +708,7 @@ async function hasOriginRemote(cwd: string): Promise<boolean> {
   return url !== null;
 }
 
-async function resolveBaseRef(repoRoot: string): Promise<string | null> {
+export async function resolveRepositoryDefaultBranch(repoRoot: string): Promise<string | null> {
   try {
     const { stdout } = await execAsync("git symbolic-ref --quiet refs/remotes/origin/HEAD", {
       cwd: repoRoot,
@@ -755,6 +755,10 @@ async function resolveBaseRef(repoRoot: string): Promise<string | null> {
   return null;
 }
 
+async function resolveBaseRef(repoRoot: string): Promise<string | null> {
+  return resolveRepositoryDefaultBranch(repoRoot);
+}
+
 function normalizeLocalBranchRefName(input: string): string {
   return input.startsWith("origin/") ? input.slice("origin/".length) : input;
 }

packages/server/src/utils/worktree.ts

@@ -668,12 +668,21 @@ export async function deriveWorktreeProjectHash(cwd: string): Promise<string> {
   }
 }
 
-async function getPaseoWorktreesRoot(cwd: string, paseoHome?: string): Promise<string> {
+export async function getPaseoWorktreesRoot(cwd: string, paseoHome?: string): Promise<string> {
   const home = paseoHome ? resolve(paseoHome) : resolvePaseoHome();
   const projectHash = await deriveWorktreeProjectHash(cwd);
   return join(home, "worktrees", projectHash);
 }
 
+export async function computeWorktreePath(
+  cwd: string,
+  slug: string,
+  paseoHome?: string
+): Promise<string> {
+  const worktreesRoot = await getPaseoWorktreesRoot(cwd, paseoHome);
+  return join(worktreesRoot, slug);
+}
+
 function normalizePathForOwnership(input: string): string {
   try {
     return realpathSync(input);