[codex] fix worktree dev dependency ergonomics (#3743)

## Thinking Path

> - Paperclip orchestrates AI agents for zero-human companies
> - Local development needs to work cleanly across linked git worktrees
because Paperclip itself leans on worktree-based engineering workflows
> - Dev-mode asset routing, Vite watch behavior, and workspace package
links are part of that day-to-day control-plane ergonomics
> - The current branch had a small but coherent set of
worktree/dev-tooling fixes that are independent from both the issue UI
changes and the heartbeat runtime changes
> - This pull request isolates those environment fixes into a standalone
branch that can merge without carrying unrelated product work
> - The benefit is a smoother multi-worktree developer loop with fewer
stale links and less noisy dev watching

## What Changed

- Serve dev public assets before the HTML shell and add a routing test
that locks that behavior in.
- Ignore UI test files in the Vite dev watch helper so the dev server
does less unnecessary work.
- Update `ensure-workspace-package-links.ts` to relink stale workspace
dependencies whenever a workspace `node_modules` directory exists,
instead of only inside linked-worktree detection paths.

## Verification

- `pnpm vitest run server/src/__tests__/app-vite-dev-routing.test.ts
ui/src/lib/vite-watch.test.ts`
- `node cli/node_modules/tsx/dist/cli.mjs
scripts/ensure-workspace-package-links.ts`

## Risks

- The asset routing change is low risk but sits near app shell behavior,
so a regression would show up as broken static assets in dev mode.
- The workspace-link repair now runs in more cases, so the main risk is
doing unexpected relinks when a checkout has intentionally unusual
workspace symlink state.

## Model Used

- OpenAI Codex, GPT-5-based coding agent in the Codex CLI environment.
Exact backend model deployment ID was not exposed in-session.
Tool-assisted editing and shell execution were used.

## Checklist

- [x] I have included a thinking path that traces from project context
to this change
- [x] I have specified the model used (with version and capability
details)
- [x] I have run tests locally and they pass
- [x] I have added or updated tests where applicable
- [x] If this change affects the UI, I have included before/after
screenshots
- [x] I have updated relevant documentation to reflect my changes
- [x] I have considered and documented any risks above
- [x] I will address all Greptile and reviewer comments before
requesting merge

scripts/ensure-workspace-package-links.ts

@@ -1,6 +1,6 @@
 #!/usr/bin/env -S node --import tsx
 import fs from "node:fs/promises";
-import { existsSync, lstatSync, readdirSync, readFileSync, realpathSync } from "node:fs";
+import { existsSync, readdirSync, readFileSync, realpathSync } from "node:fs";
 import path from "node:path";
 import { repoRoot } from "./dev-service-profile.ts";
 
@@ -43,20 +43,6 @@ function discoverWorkspacePackagePaths(rootDir: string): Map<string, string> {
   return packagePaths;
 }
 
-function isLinkedGitWorktreeCheckout(rootDir: string) {
-  const gitMetadataPath = path.join(rootDir, ".git");
-  if (!existsSync(gitMetadataPath)) return false;
-
-  const stat = lstatSync(gitMetadataPath);
-  if (!stat.isFile()) return false;
-
-  return readFileSync(gitMetadataPath, "utf8").trimStart().startsWith("gitdir:");
-}
-
-if (!isLinkedGitWorktreeCheckout(repoRoot)) {
-  process.exit(0);
-}
-
 const workspacePackagePaths = discoverWorkspacePackagePaths(repoRoot);
 const workspaceDirs = Array.from(
   new Set(
@@ -67,6 +53,11 @@ const workspaceDirs = Array.from(
 ).sort();
 
 function findWorkspaceLinkMismatches(workspaceDir: string): WorkspaceLinkMismatch[] {
+  const nodeModulesDir = path.join(repoRoot, workspaceDir, "node_modules");
+  if (!existsSync(nodeModulesDir)) {
+    return [];
+  }
+
   const packageJson = readJsonFile(path.join(repoRoot, workspaceDir, "package.json"));
   const dependencies = {
     ...(packageJson.dependencies as Record<string, unknown> | undefined),