build(vite): emit powerpoint-bridge.ps1 into out/main (#62)

The viteStaticCopy target for the PowerShell bridge had stopped emitting
anything. Two independent faults, each producing the same silent no-op:

1. vite-plugin-static-copy v4 added an `environment` option defaulting to
   `client`, and its build plugin returns early when the name does not match.
   electron-vite builds the main process in Vite's `ssr` environment, so the
   writeBundle hook never ran and no copy line was logged. The target was
   added in 38de84e against ^3.1.4 and broke on the bump to ^4.1.1.

2. `dest` reproduces the matched path's directory segments underneath itself,
   so even once the hook ran the file landed in out/main/src/main/pptx/ rather
   than out/main/. `rename: { stripBase: true }` flattens it.

This matters because src/main/pptx/windows-powershell.ts walks a list of
candidate paths for the bridge, and its `path.join(__dirname, ...)` entry
points at out/main/. That candidate has been dead since the bump, so dev and
`electron-vite preview` runs on Windows were falling through to the
`src/main/pptx/...` relative candidates, which resolve only by accident of the
working directory. Packaged builds were never affected - they resolve via
process.resourcesPath, populated from build.extraResources - which is why this
is fixed rather than deleted.

Also removes forge.config.ts. Every packaging script invokes electron-builder
and release.yml calls dist:mac / dist:win, so it described a setup the project
does not use. It was inert rather than merely redundant: no @electron-forge/*
package appears in package-lock.json, so its imports were unresolvable, and
tsconfig.json includes only src/**/*, so typecheck never read it. A leftover of
TODO.md's "Phase 11: Packaging", which specified Forge before the project
settled on electron-builder.

The bridge now also ships in the npm tarball, consistent with the `out/**`
allowlist added in #59.

Author: BernardJen

electron.vite.config.ts

@@ -10,10 +10,23 @@ export default defineConfig({
     plugins: [
       externalizeDepsPlugin(),
       viteStaticCopy({
+        // electron-vite builds the main process in Vite's `ssr` environment, but
+        // vite-plugin-static-copy v4 gained an `environment` option that defaults
+        // to `client` and silently no-ops its writeBundle hook everywhere else.
+        // Without this the target never fired and out/main/powerpoint-bridge.ps1
+        // was never emitted, leaving the __dirname lookup in
+        // src/main/pptx/windows-powershell.ts resolving against a file that did
+        // not exist.
+        environment: 'ssr',
         targets: [
           {
             src: 'src/main/pptx/powerpoint-bridge.ps1',
-            dest: '.'
+            // `dest` alone reproduces the matched path's directories underneath
+            // it, which would land the script in out/main/src/main/pptx/. The
+            // __dirname lookup expects it flat next to index.js, so strip the
+            // leading segments.
+            dest: '.',
+            rename: { stripBase: true }
           }
         ]
       })