feat(web): enable desktop webcam capture in WebPlatformService

- Updated WebPlatformService.takePicture() to use getUserMedia for webcam capture on desktop browsers, providing a live video preview and capture button in an overlay.
- Retained file input with capture attribute for mobile browsers and as a fallback if webcam access fails.
- Ensured interface and factory pattern compatibility; no changes required in PhotoDialog.vue or PlatformServiceFactory.
- Added a stub for writeAndShareFile to satisfy the PlatformService interface on web.

package.json

@@ -24,7 +24,7 @@
     "build:pywebview": "vite build --config vite.config.pywebview.mts",
     "build:electron": "npm run clean:electron && tsc -p tsconfig.electron.json && vite build --config vite.config.electron.mts && node scripts/build-electron.js",
     "build:capacitor": "vite build --mode capacitor --config vite.config.capacitor.mts",
-    "build:web": "vite build --config vite.config.web.mts",
+    "build:web": "VITE_GIT_HASH=`git log -1 --pretty=format:%h` vite build --config vite.config.web.mts",
     "electron:dev": "npm run build && electron .",
     "electron:start": "electron .",
     "clean:android": "adb uninstall app.timesafari.app || true",