build: lift Vite to 8, and get the tree out of iCloud's way

The frontend build hung on 0% CPU, roughly every other run: blocked in read()
inside libuv, no output, forever. `svelte-kit sync` alone did it too, so it was
not the bundler.

The cause was not the toolchain. `~/Documents` is iCloud-managed, and iCloud
evicts what it thinks is cold — which for a dependency tree is nearly all of it:
359 of 400 sampled files under node_modules were `dataless`. Reading an evicted
file blocks until it is downloaded again, and a download that stalls hangs the
build for good. The tell was a different error entirely: Playwright once reported
`ETIMEDOUT: connection timed out, read` while loading jsconfig.json, and
ETIMEDOUT on a local file read does not exist.

Vite 5 and esbuild 0.21 predate Node 22 and this machine runs Node 26, so they
went up anyway — to Vite 8 with @sveltejs/vite-plugin-svelte 7, which SvelteKit
2.70 takes. `package-lock.json` had to be deleted for npm to resolve it; it held
plugin 4 and rejected the whole tree with ERESOLVE. That made the build faster.
It was not what was hanging.

`engines` says Node >= 22.12 now, so the next person is told rather than left
watching a process do nothing.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

.gitignore

@@ -11,6 +11,16 @@
 
 # Frontend
 node_modules/
+# iCloud syncs ~/Documents, and it evicts what it thinks is cold — which for a
+# dependency tree is nearly all of it. An evicted file blocks on read until it is
+# downloaded again, and a download that stalls hangs the build for good: 0 % CPU,
+# no output, forever. macOS never syncs anything ending in .nosync, so the tree
+# lives there and `node_modules` is a symlink to it. Redo it after a fresh clone:
+#
+#     mv node_modules node_modules.nosync && ln -s node_modules.nosync node_modules
+#
+# The real fix is a repo path outside a synced folder.
+node_modules.nosync/
 /web/.svelte-kit/
 /web/build/