fix(hexclave): address second-wave reviewer findings (PR 3 scope)

Three small fixes from the parallel reviewers on PR 3:

1. **tanstack-start-demo vite SSR regex** — examples/tanstack-start-demo/
   vite.config.ts:76 had `noExternal: [/^@stackframe\//, ...]`. The
   regex was missed by the source rename sweep because it's a regex
   pattern, not a string literal. After the rename no @stackframe/*
   package exists in the workspace, so the regex matched nothing and
   workspace deps (`@hexclave/tanstack-start`, `@hexclave/shared`,
   `@hexclave/ui`) stopped being inlined for SSR. Without inlining,
   the Nitro server hits ERR_REQUIRE_ESM on first request because the
   CJS bundles import ESM-only transitive deps (jose, oauth4webapi).
   Flipped to /^@hexclave\// to match the renamed packages.

2. **docs.json footer GitHub link** — pointed at hexclave/stack (404,
   no such repo). The navbar at line 34 already uses hexclave/hexclave
   per the plan, so aligned the footer to match.

3. **README cleanups**:
   - Alt text 'Stack Logo' → 'Hexclave Logo' on the header image.
   - Removed broken /docs/next prefix on the setup-guide link (the
     actual docs structure is /getting-started/setup, no /docs/next).
   - contrib.rocks image now points at hexclave/hexclave (was the old
     stack-auth/stack URL).

What I did NOT touch (out of PR 3 scope, surfaced separately for a
follow-up doc-pedagogy PR):

- 14+ docs-mintlify pages teaching STACK_* env vars instead of
  HEXCLAVE_* (works via dual-read, but contradicts migration.mdx's
  'new code should use HEXCLAVE_*' recommendation).
- REST API code samples teaching X-Stack-* headers instead of
  X-Hexclave-* (works via dual-accept proxy).
- docs-mintlify/sdk/objects/stack-app.mdx broken in-page anchors
  (#stackclientapp etc. — body headings renamed in PR 2 but
  anchor IDs weren't updated).
- MCP server name inconsistency (`stack-auth` in init-prompt.ts vs
  `hexclave` in dashboard setup-page).
- The `ask_stack_auth` MCP tool was removed despite
  RENAME-TO-HEXCLAVE.md saying it should stay registered as a
  compat alias indefinitely.
- AI prompts (apps/backend/src/lib/ai/prompts.ts, apps/skills/) still
  teach legacy header / env-var names in generated code examples.

All of those are PR 2 pedagogy carry-over, not introduced by this PR,
and work functionally via the dual-read/dual-accept compat layers PR
1 + PR 2 put in place. They're documentation polish, not bugs that
block PR 3 shipping.

README.md

@@ -1,4 +1,4 @@
-[![Stack Logo](/.github/assets/logo.png)](https://hexclave.com)
+[![Hexclave Logo](/.github/assets/logo.png)](https://hexclave.com)
 
 <h3 align="center">
   <a href="https://docs.hexclave.com">📘 Docs</a>
@@ -13,7 +13,7 @@ Hexclave is a managed user authentication solution. It is developer-friendly and
 
 Hexclave gets you started in just five minutes, after which you'll be ready to use all of its features as you grow your project. Our managed service is completely optional and you can export your user data and self-host, for free, at any time.
 
-We support Next.js, React, and JavaScript frontends, along with any backend that can use our [REST API](https://docs.hexclave.com/api/overview). Check out our [setup guide](https://docs.hexclave.com/docs/next/getting-started/setup) to get started.
+We support Next.js, React, and JavaScript frontends, along with any backend that can use our [REST API](https://docs.hexclave.com/api/overview). Check out our [setup guide](https://docs.hexclave.com/getting-started/setup) to get started.
 
 <div align="center">
 <img alt="Hexclave Setup" src=".github/assets/create-project.gif" width="400" />
@@ -192,5 +192,5 @@ Note: When working with AI, you should keep a terminal tab with the dev server o
 ## ❤ Contributors
 
 <a href="https://github.com/hexclave/hexclave/graphs/contributors">
-  <img src="https://contrib.rocks/image?repo=stack-auth/stack&columns=9" width="100%" />
+  <img src="https://contrib.rocks/image?repo=hexclave/hexclave&columns=9" width="100%" />
 </a>

docs-mintlify/docs.json

@@ -219,7 +219,7 @@
   "footer": {
     "socials": {
       "x": "https://x.com/stack_auth",
-      "github": "https://github.com/hexclave/stack",
+      "github": "https://github.com/hexclave/hexclave",
       "discord": "https://discord.hexclave.com"
     }
   },

examples/tanstack-start-demo/vite.config.ts

@@ -73,7 +73,7 @@ export default defineConfig(({ mode }) => {
       dedupe: ["react", "react-dom"],
     },
     ssr: {
-      noExternal: [/^@stackframe\//, /^@radix-ui\//],
+      noExternal: [/^@hexclave\//, /^@radix-ui\//],
     },
     optimizeDeps: {
       include: ["@hexclave/shared", "@hexclave/shared/config"],