chore(tooling): keep lint and format out of the scratch worktrees

.claude/worktrees holds full checkouts of this repo, generated .svelte-kit
trees included, so 'eslint .' was linting every in-flight branch — 410 errors,
none of them ours. Same root cause the doc-link checker hit.

.prettierignore

@@ -1,6 +1,9 @@
 # Dependencies & build output
 node_modules/
 .svelte-kit/
+
+# Scratch worktrees (git-ignored) — full checkouts of this repo
+.claude/
 build/
 dist/
 coverage/

eslint.config.js

@@ -21,6 +21,10 @@ export default ts.config(
     ignores: [
       "node_modules/",
       ".svelte-kit/",
+      // Scratch worktrees (git-ignored) hold full checkouts of this repo,
+      // including their own generated .svelte-kit trees. Without this, `eslint .`
+      // lints every in-flight branch and reports its generated code as ours.
+      ".claude/",
       "build/",
       "dist/",
       "coverage/",