docs: Improve README for local development and standardize tab usage (#11865)

## Problem statement

- `<Tabs>` were not rendered in docs
- Missing steps in README for local dev

## How it was solved

- Enhance the README to better describe local development setup and
clean up formatting.
- Standardize the use of tabs across various components for consistency.

## Additional info

To not cause merge conflicts with
https://github.com/zitadel/zitadel/pull/11729 changes in
`/self-hosting/manage/configure/configure.mdx` were skipped

apps/docs/README.md

@@ -8,6 +8,12 @@ Ensure you have followed the [root quick start](../../CONTRIBUTING.md#quick-star
 
 ### Local Development
 
+Ensure all dependencies are installed:
+
+```bash
+pnpm install
+```
+
 Start the development server:
 
 ```bash
@@ -34,28 +40,61 @@ Key scripts for documentation workflows:
 
 ### Validation
 
-*   **Code Quality**: Run `pnpm lint` to check for syntax and style issues in JS/TS/MDX files.
-*   **Content Integrity**: Run `pnpm check:links` to validate content structure, including:
-    *   Broken internal links
-    *   Missing required front-matter (e.g., `title`)
-    *   Image references
+* **Code Quality**: Run `pnpm nx run @zitadel/docs:lint` to check for syntax and style issues in JS/TS/MDX files.
+* **Content Integrity**: Run `pnpm nx run @zitadel/docs:check-links` to validate content structure, including:
+  * Broken internal links
+  * Missing required front-matter (e.g., `title`)
+  * Image references
+
+### Troubleshooting
+
+#### Issue: Nx configuration not found or "nx" command not found
+
+If you see errors like:
+
+```bash
+ NX   Cannot find configuration for task @zitadel/zitadel:@zitadel/docs:generate
+
+Pass --verbose to see the stacktrace.
+```
+
+or
+
+```
+pnpm nx run @zitadel/docs:dev
+ ERR_PNPM_RECURSIVE_EXEC_FIRST_FAIL  Command "nx" not found
+
+Did you mean "pnpm nx"?
+```
+
+**Root cause**: Your dependency cache or `node_modules` is out of sync.
+
+**Solution**: Run these commands from the repository root in order:
+
+1. **Clear node_modules**: `rm -rf node_modules` — removes the installed dependency folder
+2. **Clear pnpm cache**: `pnpm cache delete` — clears pnpm's internal package cache
+3. **Reinstall dependencies**: `pnpm install` — reinstalls all dependencies fresh
+4. **Test the setup**: `pnpm nx run @zitadel/docs:generate` — verifies everything works
+
+This resolves 99% of setup-related issues.
 
 ## Contributing
 
 ### Build Process
 
-The docs build process automatically handling the following steps via `generate`:
-1.  Downloads required protoc plugins.
-2.  Generates gRPC documentation from proto files.
-3.  Generates API documentation from OpenAPI specs.
-4.  Generates index files for directory structures.
+The docs build process automatically handles the following steps via `generate`:
+
+1. Downloads required protoc plugins.
+2. Generates gRPC documentation from proto files.
+3. Generates API documentation from OpenAPI specs.
+4. Generates index files for directory structures.
 
 ### Style Guide
 
-- **Variables**: Use environment variables in code snippets where possible.
-- **Embedded Content**: Use `_filename.mdx` for content embedded in other pages (not indexed individually).
-- **Code Embedding**: Use the `file` property in code blocks to embed code from the repo.
-- **Voice**: Use active voice and sentence case for titles.
+* **Variables**: Use environment variables in code snippets where possible.
+* **Embedded Content**: Use `_filename.mdx` for content embedded in other pages (not indexed individually).
+* **Code Embedding**: Use the `file` property in code blocks to embed code from the repo.
+* **Voice**: Use active voice and sentence case for titles.
 
 Refer to the [Google Developer Style Guide](https://developers.google.com/style) for general guidelines.
 
@@ -64,9 +103,9 @@ Refer to the [Google Developer Style Guide](https://developers.google.com/style)
 All documentation content is located in the `content` directory. Note that the system strictly accepts **only `.mdx` files**.
 
 To add a new page:
-1.  Create a `.mdx` file in the appropriate subdirectory of [`content`](./content).
-2.  Register the new page in the sidebar settings at [`lib/sidebar-data.ts`](./lib/sidebar-data.ts) to make it accessible in the navigation.
 
+1. Create a `.mdx` file in the appropriate subdirectory of [`content`](./content).
+2. Register the new page in the sidebar settings at [`lib/sidebar-data.ts`](./lib/sidebar-data.ts) to make it accessible in the navigation.
 
 ### Pull Requests
 
@@ -75,9 +114,4 @@ Pass quality checks before submitting:
 
 ```bash
 pnpm nx run @zitadel/docs:build
-pnpm nx run @zitadel/docs:check:links
 ```
-
-You can also run specific steps individually:
-*   `pnpm fetch:remote-content`
-*   `pnpm generate:api-reference`