[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

ui/src/lib/vite-watch.test.ts

@@ -0,0 +1,29 @@
+import { describe, expect, it } from "vitest";
+import { createUiDevWatchOptions, shouldIgnoreUiDevWatchPath } from "./vite-watch";
+
+describe("shouldIgnoreUiDevWatchPath", () => {
+  it("ignores test-only files and folders", () => {
+    expect(shouldIgnoreUiDevWatchPath("/repo/ui/src/components/IssuesList.test.tsx")).toBe(true);
+    expect(shouldIgnoreUiDevWatchPath("/repo/ui/src/lib/issue-tree.spec.ts")).toBe(true);
+    expect(shouldIgnoreUiDevWatchPath("/repo/ui/src/__tests__/helpers.ts")).toBe(true);
+    expect(shouldIgnoreUiDevWatchPath("/repo/ui/tests/helpers.ts")).toBe(true);
+  });
+
+  it("keeps runtime source files watchable", () => {
+    expect(shouldIgnoreUiDevWatchPath("/repo/ui/src/components/IssuesList.tsx")).toBe(false);
+    expect(shouldIgnoreUiDevWatchPath("/repo/ui/src/pages/IssueDetail.tsx")).toBe(false);
+  });
+});
+
+describe("createUiDevWatchOptions", () => {
+  it("preserves the WSL /mnt polling fallback", () => {
+    expect(createUiDevWatchOptions("/mnt/c/paperclip")).toMatchObject({
+      usePolling: true,
+      interval: 1000,
+    });
+  });
+
+  it("always includes the ignored-path predicate", () => {
+    expect(createUiDevWatchOptions("/Users/dotta/paperclip")).toHaveProperty("ignored");
+  });
+});

ui/src/lib/vite-watch.ts

@@ -0,0 +1,29 @@
+const TEST_DIRECTORY_NAMES = new Set([
+  "__tests__",
+  "_tests",
+  "test",
+  "tests",
+]);
+
+const TEST_FILE_BASENAME_RE = /\.(test|spec)\.[^/]+$/i;
+
+export function shouldIgnoreUiDevWatchPath(watchedPath: string): boolean {
+  const normalizedPath = String(watchedPath).replaceAll("\\", "/");
+  if (normalizedPath.length === 0) return false;
+
+  const segments = normalizedPath.split("/");
+  const basename = segments.at(-1) ?? normalizedPath;
+
+  return segments.some((segment) => TEST_DIRECTORY_NAMES.has(segment))
+    || TEST_FILE_BASENAME_RE.test(basename);
+}
+
+export function createUiDevWatchOptions(currentWorkingDirectory: string) {
+  return {
+    ignored: shouldIgnoreUiDevWatchPath,
+    // WSL2 /mnt/ drives don't support inotify — fall back to polling so HMR works.
+    ...(currentWorkingDirectory.startsWith("/mnt/")
+      ? { usePolling: true, interval: 1000 }
+      : {}),
+  };
+}

ui/vite.config.ts

@@ -2,6 +2,7 @@ import path from "path";
 import { defineConfig } from "vite";
 import react from "@vitejs/plugin-react";
 import tailwindcss from "@tailwindcss/vite";
+import { createUiDevWatchOptions } from "./src/lib/vite-watch";
 
 export default defineConfig(({ mode }) => ({
   plugins: [react(), tailwindcss()],
@@ -23,8 +24,7 @@ export default defineConfig(({ mode }) => ({
   },
   server: {
     port: 5173,
-    // WSL2 /mnt/ drives don't support inotify — fall back to polling so HMR works
-    watch: process.cwd().startsWith("/mnt/") ? { usePolling: true, interval: 1000 } : undefined,
+    watch: createUiDevWatchOptions(process.cwd()),
     proxy: {
       "/api": {
         target: "http://localhost:3100",