fix: use Vite virtual module for configuration instead of global state

The initial config-store approach failed because Astro's injected routes
run in isolated contexts during prerendering and don't have access to
global state set during astro:config:setup.

Solution: Created a Vite plugin that provides the configuration through
a virtual module (virtual:@astrojs/discovery/config) which routes can
import at build time.

Changes:
- Added Vite plugin in astro:config:setup hook
- Updated all route handlers to import from virtual module
- Changed version from date-based (2025.11.03) to semantic (1.0.0) per npm requirements
- Added @ts-ignore comments for virtual module imports

Testing: Verified in test project that all configuration now properly
passes through to generated files (robots.txt, llms.txt, humans.txt).

example/EXAMPLE_OUTPUT.md

@@ -0,0 +1,195 @@
+# Example Generated Files
+
+This document shows what the generated discovery files look like.
+
+## Example robots.txt
+
+```
+# robots.txt
+# Generated by @astrojs/discovery for example.com
+
+User-agent: *
+Allow: /
+
+# Sitemaps
+Sitemap: https://example.com/sitemap-index.xml
+
+# LLM-specific resources
+# AI assistants can find additional context at /llms.txt
+# See: https://github.com/anthropics/llm-txt
+
+User-agent: Anthropic-AI
+User-agent: Claude-Web
+User-agent: GPTBot
+User-agent: ChatGPT-User
+User-agent: cohere-ai
+User-agent: Google-Extended
+User-agent: PerplexityBot
+User-agent: Applebot-Extended
+Allow: /llms.txt
+Allow: /llms-full.txt
+
+# Crawl delay (be nice to our server)
+Crawl-delay: 1
+```
+
+## Example llms.txt
+
+```
+# example.com
+
+> An awesome web development platform built with Astro
+
+---
+
+## Site Information
+
+- **URL**: https://example.com/
+- **Description**: An awesome web development platform built with Astro
+
+## Key Features
+
+- Lightning-fast static site generation
+- Built-in SEO optimization
+- AI-powered content suggestions
+- Modern component architecture
+
+## Important Pages
+
+- **[Documentation](https://example.com/docs)**
+  Complete API documentation and guides
+- **[Blog](https://example.com/blog)**
+  Latest articles and tutorials
+- **[Examples](https://example.com/examples)**
+  Real-world code examples
+
+## Instructions for AI Assistants
+
+When helping users with our site:
+1. Check documentation first at /docs
+2. Use provided API endpoints for dynamic queries
+3. Follow brand guidelines for tone and style
+4. Be helpful, accurate, and concise
+5. Provide code examples when relevant
+
+## API Endpoints
+
+- `POST /api/chat`
+  Chat endpoint for real-time conversations
+  Full URL: https://example.com/api/chat
+- `GET /api/search`
+  Search API for site content
+  Full URL: https://example.com/api/search
+- `POST /api/generate`
+  AI content generation endpoint
+  Full URL: https://example.com/api/generate
+
+## Technical Stack
+
+- **Frontend**: Astro, TypeScript, React, Tailwind CSS
+- **Backend**: Node.js, FastAPI, PostgreSQL
+- **AI/ML**: Claude, GPT-4, LangChain
+- **Other**: Docker, Redis, Nginx
+
+## Brand Voice & Guidelines
+
+- Professional yet friendly and approachable
+- Technical but accessible to beginners
+- Focus on practical, real-world examples
+- Encourage experimentation and learning
+- Community-focused and inclusive
+
+---
+
+**Last Updated**: 2025-11-03
+
+*This file was generated by [@astrojs/discovery](https://github.com/withastro/astro-discovery)*
+```
+
+## Example humans.txt
+
+```
+/* TEAM */
+
+  Name: Jane Doe
+  Role: Creator & Lead Developer
+  Contact: jane@example.com
+  From: San Francisco, CA
+  Twitter: @janedoe
+  GitHub: janedoe
+
+  Name: John Smith
+  Role: Designer & UX Architect
+  Contact: john@example.com
+  From: New York, NY
+  Twitter: @johnsmith
+  GitHub: johnsmith
+
+/* THANKS */
+
+  The Astro team for creating amazing tools
+  Open source community for endless inspiration
+  Coffee ☕ for making this all possible
+  Stack Overflow for solving impossible bugs
+
+/* SITE */
+
+  Last update: 2025-11-03
+  Language: English
+  Doctype: HTML5
+  IDE: VS Code
+  Tech Stack: Astro, TypeScript, React, Tailwind CSS, Node.js
+  Standards: HTML5, CSS3, ES2022, WCAG 2.1
+  Components: Astro Components, React Components, Custom Web Components
+  Software: VS Code, Git, Docker, Figma
+
+/* THE STORY */
+
+  This project started in early 2025 when we realized that the web needed
+  better discovery mechanisms. Search engines were getting smarter, AI
+  assistants were becoming ubiquitous, but websites weren't adapting.
+
+  We wanted to build something that made it trivially easy for Astro
+  developers to make their sites discoverable by everyone - from Google
+  to Claude to curious humans browsing the source.
+
+  After countless cups of coffee and late-night coding sessions, we
+  launched @astrojs/discovery. It's been an incredible journey!
+
+/* FUN FACTS */
+
+  Built with love, powered by coffee and determination
+  Over 200 commits in the first month
+  Designed with accessibility and inclusivity at the core
+  Zero runtime JavaScript on the client
+  100% test coverage from day one
+
+/* PHILOSOPHY */
+
+  "Make the web more discoverable, one site at a time"
+  "Embrace open standards and protocols"
+  "Build with the future in mind, but ship today"
+  "Developer experience matters as much as user experience"
+  "Documentation is code, treat it with respect"
+
+/* SUSTAINABILITY */
+
+  This site is carbon neutral and hosted on renewable energy servers.
+  We measure our environmental impact and offset our carbon emissions.
+  Building a better web means building a sustainable web.
+```
+
+## Example sitemap-index.xml
+
+```xml
+<?xml version="1.0" encoding="UTF-8"?>
+<sitemapindex xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">
+  <sitemap>
+    <loc>https://example.com/sitemap-0.xml</loc>
+  </sitemap>
+</sitemapindex>
+```
+
+---
+
+These files are automatically generated based on your configuration in `astro.config.mjs`. Customize them by adjusting the configuration options!