refactor(gui): remove the Services system, flatten into plain singleton modules

[jelveh]

What

Removes the GUI's mini service framework (src/gui/src/services/) and flattens it into plain ES-module singletons.

The old system had:

• a Service base class (in definitions.js) with construct/init/__on/context magic
• a globalThis.services string-keyed registry with a two-phase construct→init lifecycle and an emit/__on_* event bus
• a frontend↔backend service_script bridge (window.service_script / service_script_api_promise / PuterHomepageService.registerScript) for registering extra services from the backend

Nothing used the extension bridge, and the framework was indirection over what are really just nine long-lived singletons.

Changes

• Move the nine services to src/gui/src/modules/ as plain classes exporting a singleton: process, exec, ipc, broadcast, theme, debug, locale, anti-csrf. __launch-on-init becomes a plain launch_on_init(gui_params) function (nothing else referenced it). Method bodies are unchanged.
• Direct imports replace globalThis.services.get(name) at every call site (IPC.js, helpers.js, helpers/launch_app.js, UIDesktop.js, UIWindowThemeDialog.js, UIWindowTaskManager.js, UIWindowNewPassword.js, UIWindowManageSessions.js, and cross-module refs).
• The single gui:ready event (the only user of the event bus) becomes a direct process_service.on_gui_ready() call from UIDesktop.
• launch_services() now just calls init() on the four modules that need runtime setup (exec/debug/theme/process), then runs launch_on_init. All singletons are constructed at import time, so the original construct-before-init ordering is preserved.
• Remove the Service base class from definitions.js.
• Remove the unused service_script bridge from PuterHomepageService (the window.service_script shim, registerScript, #serviceScripts, and the serviceScriptTags injection point).

No container, no string-keyed registry, no base-class lifecycle, no event emitter, no backend bridge — just singletons wired by import.

Net: +121 / −253 lines across 20 files (renames preserved).

Testing

• webpack GUI build: clean (only pre-existing asset-size warnings)
• backend tsc -p tsconfig.build.json: 0 errors
• HomepageController.test.ts: 8/8 pass (validates the shell HTML still renders after the service_script removal)
• Booted the app and exercised it in the browser with no console errors:
  • desktop + dashboard render
  • File Manager window opens
  • launching an SDK app (Dev Center) → registered as a process
  • Task Manager shows the correct process tree (Puter/Init, explorer/UI, dev-center/App) — validates process_service init + register + tree

[github-actions]

Coverage Report

Status	Category	Percentage	Covered / Total
🔵	Lines	76.06% 🟰 ±0%	16221 / 21324
🔵	Statements	74.32% ⬆️ +0.01%	17264 / 23228
🔵	Functions	72.85% ⬆️ +0.03%	2698 / 3703
🔵	Branches	62.85% 🟰 ±0%	11290 / 17963

File Coverage

File	Stmts	Branches	Functions	Lines	Uncovered Lines
Changed Files
src/backend/services/homepage/PuterHomepageService.ts	70.76% ⬆️ +1.20%	60.6% 🟰 ±0%	77.77% ⬆️ +14.14%	73.77% ⬆️ +1.47%	83, 93-103, 123-132, 204, 325-339, 349, 357-365

Generated in workflow #538 for commit bc3f778 by the Vitest Coverage Report Action