fix(shell-docs): unbreak preview build + harden related regressions

Three regressions from the earlier CR Round 1 fix batch + a related
miss the same round didn't catch.

1. `components/ai/page-actions.tsx` is `"use client"`; importing
   `getBaseUrl` from `@/lib/sitemap-helpers` pulled `fs` / `path` /
   `gray-matter` into the client bundle and broke the build entirely
   ("Module not found: Can't resolve 'fs'"). The whole point of
   `getBaseUrl` is the 2-line env-var read + trailing-slash strip — no
   filesystem work — so inline a `getClientBaseUrl()` helper here with a
   pointer to the canonical server-side version. `sitemap-helpers.ts`
   stays untouched so other server-side callers keep their convenience.

2. The same file re-threw caught errors from `fetchMarkdown` /
   `clipboard.writeText` on the assumption that Fumadocs's
   `useCopyButton` would treat the rejection as "don't flip the
   `checked` state". It doesn't — there's no `.catch()` on the
   internal promise (verified in
   `fumadocs-ui/dist/utils/use-copy-button.js`), so the throw produced
   an unhandled rejection (browser console noise + Sentry spam) AND
   gave the user no visible failure indicator either way. Log and
   swallow at this layer; a follow-up PR can introduce an explicit
   error UI if we want "Copy failed" to surface.

3. `.claude/launch.json` routed `shell` to port 3004 by passing
   `-- --port 3004` to `npm --prefix showcase/shell run dev`. But
   shell's `dev` script ends with `npx -y concurrently -k -n
   bundle,next "tsx ... --watch" "next dev"` — the trailing
   `--port 3004` was parsed by `concurrently`, not `next dev`, so
   `next dev` still bound 3000 and the original collision with `docs`
   persisted. Switch to `bash -c "PORT=3004 npm --prefix showcase/shell
   run dev"` so the env var passes through `concurrently` into
   `next dev` (which natively reads PORT).

Call-site enumeration:
- `getClientBaseUrl` (new) — only used inside the same file. No
  external callers to update.
- `getBaseUrl` (untouched in `@/lib/sitemap-helpers`) — server-side
  callers (sitemap routes, `llms-full.txt` route, `llms.txt` route)
  unchanged; verified via grep that no `"use client"` file imports it.
- `MarkdownCopyButton` — error now logged once via `console.error`
  and swallowed; the button stays in its idle state.
- `.claude/launch.json` `shell` entry — `runtimeExecutable` flipped
  from `npm` to `bash`; harness reads these as opaque strings.

Author: tylerslaton

.claude/launch.json

@@ -15,16 +15,8 @@
     },
     {
       "name": "shell",
-      "runtimeExecutable": "npm",
-      "runtimeArgs": [
-        "--prefix",
-        "showcase/shell",
-        "run",
-        "dev",
-        "--",
-        "--port",
-        "3004"
-      ],
+      "runtimeExecutable": "bash",
+      "runtimeArgs": ["-c", "PORT=3004 npm --prefix showcase/shell run dev"],
       "port": 3004
     },
     {

showcase/shell-docs/src/components/ai/page-actions.tsx

@@ -17,7 +17,6 @@ import {
 } from "@/components/ui/popover";
 import { buttonVariants } from "@/components/ui/button";
 import { usePathname } from "fumadocs-core/framework";
-import { getBaseUrl } from "@/lib/sitemap-helpers";
 import ClaudeIcon from "@/components/icons/claude";
 import ClaudeCodeIcon from "@/components/icons/claude-code";
 import CodexIcon from "@/components/icons/codex";
@@ -28,6 +27,21 @@ import WindsurfIcon from "@/components/icons/windsurf";
 // awaited STRING (not a Promise) to avoid the failed-fetch poisoning
 // pattern where a rejected promise gets cached and replayed on every
 // subsequent click — see `fetchMarkdown` below.
+/**
+ * Resolve the canonical base URL on the client. Inlined here (instead of
+ * imported from `@/lib/sitemap-helpers`) because that module also pulls
+ * in `fs` / `path` / `gray-matter` for sitemap generation — Node-only
+ * deps that fail the Next.js client bundle when this `"use client"`
+ * component reaches for them. The env var contract is identical:
+ * `NEXT_PUBLIC_BASE_URL` (set in production), prod fallback otherwise,
+ * with trailing slash stripped so callers can concatenate
+ * `${BASE}${path}` safely.
+ */
+function getClientBaseUrl(): string {
+  const raw = process.env.NEXT_PUBLIC_BASE_URL || "https://docs.copilotkit.ai";
+  return raw.replace(/\/+$/, "");
+}
+
 const cache = new Map<string, string>();
 
 /** Fetch the markdown body for a docs URL, caching successful responses
@@ -73,11 +87,15 @@ export function MarkdownCopyButton({
       const body = await fetchMarkdown(markdownUrl);
       await navigator.clipboard.writeText(body);
     } catch (err) {
-      // Surface for support / on-page diagnostics, but don't flip the
-      // copied indicator (useCopyButton respects throws by not setting
-      // `checked`, so the button visually fails-shut).
+      // Log for support / on-page diagnostics. Do NOT re-throw: Fumadocs's
+      // `useCopyButton` does not attach a `.catch()` to its internal
+      // promise, so a throw here becomes an unhandled rejection (browser
+      // console noise + Sentry spam) without any user-visible feedback
+      // — the button stays in its idle state either way. Swallowing
+      // here keeps the failure mode loud-but-bounded; a follow-up PR
+      // can introduce an explicit error UI state if we want the user
+      // to see "Copy failed".
       console.error("[page-actions] Copy Markdown failed", markdownUrl, err);
-      throw err;
     } finally {
       setLoading(false);
     }
@@ -128,15 +146,15 @@ export function ViewOptionsPopover({
 }) {
   const pathname = usePathname();
   const items = useMemo(() => {
-    // Build the absolute URL deterministically from `getBaseUrl()` so
-    // SSR and the first client render agree. The previous
+    // Build the absolute URL deterministically from `getClientBaseUrl()`
+    // so SSR and the first client render agree. The previous
     // `typeof window === "undefined" ? pathname : new URL(pathname, ...)`
     // branch produced a relative path on the server and an absolute URL
     // on the client, causing a React hydration mismatch on every
     // popover anchor AND embedding a path-only URL ("Read /quickstart,
     // I want to ask...") into the LLM-app deep-link prompt — which the
     // target LLM can't resolve.
-    const pageUrl = `${getBaseUrl()}${pathname}`;
+    const pageUrl = `${getClientBaseUrl()}${pathname}`;
     const q = `Read ${pageUrl}, I want to ask questions about it.`;
 
     return [