A dev server start whose IPC call rejects leaves the button dead for the session

Description

Found by the self-review of #500, pre-existing. In startPhpServer (src/renderer/index.jsx, the catch after window.api.startServer), a rejected start clears starting and serverStartRequestedRef but never devServerActiveRef.current. The button goes back to reading Start dev server, and toggleDevServer's first guard (if (devServerActiveRef.current) return;, the #488 double-click guard) then swallows every later click silently. Nothing short of reopening the app brings the server back.

Only reachable when the IPC itself rejects (the res.ok === false path goes through stopDevServer and is fine), so it has not been seen in a pass; #500's no-watch start inherits it unchanged and does not make it more reachable.

Fix: clear devServerActiveRef.current in that catch, beside setStarting(false), and say in the Server tab that the start failed. A unit-level test needs the start decision extracted to a module first (see .github/instructions/code-review.instructions.md, renderer decisions live in modules).

Related

#500, #488.

Start in src/renderer/index.jsx at the catch after window.api.startServer in startPhpServer, then read .github/instructions/code-review.instructions.md for the renderer decision-module guidance. Ensure a rejected IPC start clears the active state and reports failure in the Server tab, and add a unit-level test after extracting the start decision to a module.