Run prettier across the repo, exclude the lockfile from it

Prettier had never been run in --check mode here before, so this had
drifted across most files (markdown tables, long option() chains,
line wrapping). Purely formatting, no logic changes - needed so a CI
format:check gate can actually pass. Adds .prettierignore for
pnpm-lock.yaml specifically: prettier's YAML formatter rewrites every
quoted key (single -> double quotes) producing an ~8700-line diff of
pure noise on a file pnpm itself owns the formatting of.

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

src/app/layout.tsx

@@ -1,5 +1,9 @@
 import type { Metadata } from "next";
-import { Bricolage_Grotesque, IBM_Plex_Mono, IBM_Plex_Sans } from "next/font/google";
+import {
+  Bricolage_Grotesque,
+  IBM_Plex_Mono,
+  IBM_Plex_Sans,
+} from "next/font/google";
 import { ThemeProvider } from "next-themes";
 import { TooltipProvider } from "@/components/ui/tooltip";
 import { Toaster } from "@/components/ui/sonner";