docs: rewrite high-traffic pages as actionable step-by-step guides (#530)

* docs(config): rewrite overview with FileTree and restart guide

- Replace vague marketing copy with actionable config guide
- Add FileTree showing 4 config files (.env, librechat.yaml, docker-compose.yml, docker-compose.override.yml)
- Add file descriptions explaining what each config file controls
- Add restart Callout with Docker/Local tabs
- Add next-step Cards linking to librechat.yaml setup, Docker setup, .env reference

* docs(config): restructure librechat.yaml with guide-first setup steps

- Replace feature list with 4-step setup procedure using Steps component
- Add Docker/Local Tabs for deployment-specific commands
- Add OpenRouter worked example with OPENROUTER_KEY warning
- Add Reference section with Cards linking to ai_endpoints and object_structure
- Merge troubleshooting content from setup.mdx into index page
- Remove outdated model menu screenshots

* refactor(config): merge setup.mdx into librechat.yaml and add redirect

- Delete setup.mdx (content merged into index.mdx)
- Remove setup from meta.json pages array
- Update ai_endpoints link from /setup to /librechat_yaml
- Add redirect for old /setup URL in next.config.mjs

* docs(endpoints): rewrite OpenRouter as end-to-end setup guide

- Replace bare YAML snippet with 5-step Steps component guide
- Add OPENROUTER_KEY vs OPENROUTER_API_KEY warning callout
- Add Docker/Local restart Tabs and verification step
- Add customization section and reference Cards
- Remove deprecated GitHub screenshot image

* docs(setup): rewrite Docker install with first-login flow and troubleshooting

- Add Steps-based installation with clone, env, start, and verify steps
- Document first account = admin behavior at localhost:3080
- Add librechat.yaml volume mounting section with override file pattern
- Add troubleshooting for port conflicts, container crashes, missing env vars
- Replace deprecated Additional Links with Cards component for next steps
- Cross-link to librechat.yaml guide, Docker override guide, and .env reference

* docs(endpoints): add file context and activation steps to custom endpoints

- Add 'Which File Does What' callout explaining librechat.yaml, .env, and docker-compose.override.yml roles
- Rewrite Step 4 as 'Restart and Verify' with Docker/Local Tabs
- Add troubleshooting callout for missing endpoints
- Replace deprecated AdditionalLinks with Cards for next steps
- Link to Configuration Overview for file relationship context

* docs(endpoints): fix OpenRouter Step tag indentation

* fix(docs): replace empty user guides hub with Cards and remove stale screenshot

- Rewrite user_guides/index.mdx as Cards hub with Guides and Popular Features sections
- Add cross-links to Agents, Image Gen, Web Search, and MCP feature pages
- Remove stale screenshot from LiteLLM page (110412045 asset)
- Verify auth section Next button works (SAML/auth0 -> pre_configured_ai)
- Verify S3 page has all required sections (no changes needed)

* docs(features): add Quick Start guide and cross-links to image generation

* docs(tools): rewrite Google Search with agent-first Steps and cross-links

* chore: update .gitignore

* fix: make Docker/Local tabs switch content when clicked

The TabCompat wrapper was rendering <Tabs.Tab> as plain <div> elements,
which never registered with fumadocs' internal tab context. Clicking tab
triggers had no effect because the content panels didn't respond to state
changes.

Fix: assign the real fumadocs Tab component as TabsCompat.Tab via
Object.assign, so <Tabs.Tab> in MDX renders the real Tab that registers
with the parent Tabs context. Keep standalone <Tab> (from auto-generated
code blocks with filename=) as a plain div fallback to avoid crashes
when there is no parent Tabs context.

next.config.mjs

@@ -58,6 +58,7 @@ const nonPermanentRedirects = [
   ['/docs/user_guides/rag_api', '/docs/features/rag_api'],
   ['/docs/user_guides/plugins', '/docs/features/agents'],
   ['/docs/features/plugins', '/docs/features/agents'],
+  ['/docs/configuration/librechat_yaml/setup', '/docs/configuration/librechat_yaml'],
 ];
 
 /**