chore(cale): gitignore the generated index, and drop the dep nothing imports

`public/kits.json` is a 1.2 MB snapshot of audio that lives outside the repo, and
`.kitindex-cache.json` is derived from file mtimes — both regenerate in seconds and
neither belongs in history.

@strudel/web went in while working out whether the sequencer should be a Strudel
playground. It should not: the deck already plays the rack with `loopAt` semantics,
and a second audio graph would only add a way for the two to disagree about what
the same cells mean. The Strudel tab emits text for strudel.cc instead. So the
package comes back out — a dependency nothing imports is a false statement about
what the project needs, and it would have shipped in the lockfile forever.

armada/ui/.gitignore

 node_modules
 dist
 *.log
+
+# Generated by tools/foundry/kitindex.py from the sample root — a 1.2 MB snapshot of
+# audio that lives outside the repo. Regenerate, don't commit.
+public/kits.json

armada/ui/package.json

@@ -13,7 +13,6 @@
   "dependencies": {
     "@fontsource-variable/geist": "^5.2.9",
     "@fontsource-variable/geist-mono": "^5.2.8",
-    "@strudel/web": "^1.3.0",
     "@wavesurfer/react": "^1.0.12",
     "clsx": "^2.1.1",
     "lucide-react": "^1.17.0",

tools/foundry/.gitignore

 __pycache__/
 *.pyc
 .pytest_cache/
+
+# kitindex envelope cache — derived, keyed on file size+mtime
+.kitindex-cache.json