fix: serve built SPA from dist when web-server runs from source

[nmbrthirteen]

Problem

npm run ui (tsx src/ui/web-server.ts) booted fine but 500'd on first page load:

Error: ENOENT: no such file or directory, stat '...\src\ui\public\index.html'

The server resolves its static dir relative to its own file (__dirname/public). Running from source that's src/ui/public, which only holds static assets — the SPA index.html is emitted by vite build into dist/ui/public. So the dev server had no index.html to serve. (Prod, node dist/ui/web-server.js, was always fine.)

Fix

Resolve publicDir once: use __dirname/public when it contains index.html, otherwise fall back to the built dist/ui/public. Both express.static and the SPA fallback route now use it. Prod behavior is unchanged; npm run ui now works after a build.

Verify

• tsc --noEmit: clean
• vitest: 47/47

Summary by CodeRabbit

• Refactor
  • Enhanced server configuration for improved asset resolution and deployment flexibility. The application now intelligently locates and serves frontend resources from multiple sources with better fallback mechanisms. Single-page application routing has been improved to work reliably across different deployment environments.

[coderabbitai]

Caution

Review failed

Pull request was closed or merged during review

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: e6692554-e73c-47d8-8a4f-641731d54d61

📥 Commits

Reviewing files that changed from the base of the PR and between e085d46 and 9c93d94.

📒 Files selected for processing (1)

• src/ui/web-server.ts

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📝 Walkthrough

Walkthrough

src/ui/web-server.ts now centralizes frontend static directory resolution via a publicDir constant that prefers a local public/index.html and falls back to the built distribution at dist/ui/public. This constant is applied to both Express static middleware and the SPA fallback route.

Changes

Frontend static directory resolution

Layer / File(s)	Summary
Frontend static directory resolution and application src/ui/web-server.ts	A publicDir constant intelligently selects the frontend static directory by checking for public/index.html next to the server or falling back to dist/ui/public. This constant replaces hardcoded __dirname/public paths in both the Express static middleware and the SPA fallback response route.

🎯 1 (Trivial) | ⏱️ ~3 minutes

🐰 A hopping change so fine and neat,
One constant makes the logic sweet,
No more hardcoded paths in sight,
The static server gets it right!

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title directly reflects the main fix: resolving the SPA serving issue by falling back to the dist directory when running from source.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch fix/ui-dev-static-fallback

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