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/cli/lib/network.ts

@@ -51,10 +51,18 @@ export async function isServerReachable(url: string): Promise<boolean> {
 
 export function openBrowser(url: string): void {
   const command =
-    process.platform === "darwin" ? "open" : process.platform === "win32" ? "start" : "xdg-open";
+    process.platform === "darwin"
+      ? "open"
+      : process.platform === "win32"
+        ? "start"
+        : "xdg-open";
   const args = process.platform === "win32" ? ["", url] : [url];
   try {
-    spawn(command, args, { detached: true, stdio: "ignore", shell: process.platform === "win32" }).unref();
+    spawn(command, args, {
+      detached: true,
+      stdio: "ignore",
+      shell: process.platform === "win32",
+    }).unref();
   } catch {
     // best-effort - not fatal if no browser opener is available
   }