Add tests for config error reporting and multi-vhost startup

Test that the server correctly reports missing certificate errors,
rejects invalid hostnames, fails gracefully on port conflicts, and
starts successfully with multiple virtual hosts configured.

AGENTS.md

@@ -1,135 +1,38 @@
-# Overview
-This project is a very simple gemini server which only serves static files,
-nothing else. It is meant to be generic so other people can use it.
+# AGENTS.md
 
-# Build/Test/Lint Commands
-
-## Core Commands
-- `cargo build` - Build the project
-- `cargo build --release` - Build optimized release version
-- `cargo run` - Run the server with default config
-- `cargo test` - Run all unit tests
-- `cargo test <test_name>` - Run a specific test
-- `cargo test <module>::tests` - Run tests in a specific module
-- `cargo clippy` - Run linter checks for code quality
-- `cargo clippy --fix` - Automatically fix clippy suggestions
-- `cargo clippy --bin <name>` - Check specific binary
-- `cargo fmt` - Format code according to Rust standards
-- `cargo check` - Quick compile check without building
-
-## Common Test Patterns
-- `cargo test config::tests` - Run config module tests
-- `cargo test request::tests` - Run request handling tests
-- `cargo test -- --nocapture` - Show println output in tests
-
-# Code Style Guidelines
-
-## Imports
-- Group imports: std libs first, then external crates, then local modules
-- Use `use crate::module::function` for internal imports
-- Prefer specific imports over `use std::prelude::*`
-- Keep imports at module level, not inside functions
-
-## Code Structure
-- Use `#[tokio::main]` for async main function
-- Keep functions small and focused (single responsibility)
-- Use `const` for configuration values that don't change
-- Error handling with `Result<T, E>` and `?` operator
-- Use `tracing` for logging, not `println!` in production code
-
-## Naming Conventions
-- `PascalCase` for types, structs, enums
-- `snake_case` for functions, variables, modules
-- `SCREAMING_SNAKE_CASE` for constants
-- Use descriptive names that indicate purpose
-
-## Error Handling
-- Use `io::Result<()>` for I/O operations
-- Convert errors to appropriate types with `map_err` when needed
-- Use `unwrap()` only in tests and main() for unrecoverable errors
-- Use `expect()` with meaningful messages for debugging
-- Return early with `Err()` for validation failures
-
-## Security Requirements
-- **Critical**: Always validate file paths with `path_security::validate_path`
-- Never construct paths from user input without validation
-- Use timeouts for network operations (`tokio::time::timeout`)
-- Limit request sizes (see `MAX_REQUEST_SIZE` constant)
-- Validate TLS certificates properly
-- Never expose directory listings
-
-## Testing Guidelines
-- Use `tempfile::TempDir` for temporary directories in tests
-- Test both success and error paths
-- Use `#[cfg(test)]` for test modules
-- Create temporary test files in `tmp/` directory
-- Test security boundaries (path traversal, invalid inputs)
-- Use `assert_eq!` and `assert!` for validations
-
-## Lint Checking
-- `cargo clippy` - Run linter checks for code quality
-- `cargo clippy --fix` - Automatically fix clippy suggestions
-- `cargo clippy --bin <name>` - Check specific binary
-- `cargo fmt` - Format code to match Rust standards
-- **Run clippy before every commit** - Address all warnings before pushing code
-- Current clippy warnings (2025-01-15):
-  - src/server.rs:16-17 - Unnecessary borrows on file_path
-  - src/logging.rs:31 - Match could be simplified to let statement
+## Introduction
+This is a modern Rust project for a Gemini server. Follow these guidelines for
+development, testing, and security.
 
 ## Testing
-- Run `cargo test` before every commit to prevent regressions
-- Pre-commit hook automatically runs full test suite
-- Rate limiting integration test uses separate port for isolation
-- All tests must pass before commits are allowed
-- Test suite includes: unit tests, config validation, rate limiting under load
+- Use unit tests for individual components and integration tests for
+  end-to-end features.
+- Test at appropriate levels to ensure reliability.
 
-## Async Patterns
-- Use `.await` on async calls
-- Prefer `tokio::fs` over `std::fs` in async contexts
-- Handle timeouts for network operations
-- Use `Arc<Clone>` for shared data across tasks
+## Development Practices
+- Do not remove features unless explicitly ordered, especially those
+  mentioned in README.md.
+- Pre-commit hooks run all tests before commits.
+- Follow modern Rust best practices.
+- Fix all compiler warnings before committing—they often indicate future bugs.
 
-## Gemini Protocol Specific
-- Response format: "STATUS META\r\n"
-- Status 20: Success (follow with MIME type)
-- Status 41: Server unavailable (timeout, overload)
-- Status 51: Not found (resource doesn't exist)
-- Status 59: Bad request (malformed URL, protocol violation)
-- Default MIME: "text/gemini" for .gmi files
-- Default file: "index.gmi" for directory requests
+## Security
+- Cybersecurity is critical. Never remove guards for remote user input
+  validation, such as URLs or file paths.
 
-## Error Handling
-- **Concurrent request limit exceeded**: Return status 41 "Server unavailable"
-- **Timeout**: Return status 41 "Server unavailable" (not 59)
-- **Request too large**: Return status 59 "Bad request"
-- **Empty request**: Return status 59 "Bad request"
-- **Invalid URL format**: Return status 59 "Bad request"
-- **Hostname mismatch**: Return status 59 "Bad request"
-- **Path resolution failure**: Return status 51 "Not found" (including security violations)
-- **File not found**: Return status 51 "Not found"
-- Reject requests > 1024 bytes (per Gemini spec)
-- Reject requests without proper `\r\n` termination
-- Use `tokio::time::timeout()` for request timeout handling
-- Configurable concurrent request limit: `max_concurrent_requests` (default: 1000)
+## Planning and Tracking
+- Use local BACKLOG.md to see planned work.
+- For multi-phase changes, add TODO items below the user story with checkboxes
+  and update them during implementation.
 
-## Configuration
-- TOML config files with `serde::Deserialize`
-- CLI args override config file values
-- Required fields: root, cert, key, host
-- Optional: port, log_level, max_concurrent_requests
+## Tools
+- Use cargo for building and testing.
+- Run clippy for code quality checks.
+- Use fmt for code formatting.
+- Use --quiet flag to suppress startup output during testing.
+- Follow project-specific tool usage as needed.
 
-# Development Notes
-- Generate self-signed certificates for local testing in `tmp/` directory
-- Use CN=localhost for development
-- Fix every compiler warning before committing any code
-- Create temporary files in the tmp/ directory for your tests like .gem files
-  or images, etc., so they are gitignored
-- Use `path-security` crate for path validation
-- Default port: 1965 (standard Gemini port)
-- Default host: 0.0.0.0 for listening
-- Log level defaults to "info"
-
-## Environment Setup
-- Install clippy: `rustup component add clippy`
-- Ensure `~/.cargo/bin` is in PATH (add `source "$HOME/.cargo/env"` to `~/.bashrc`)
-- Verify setup: `cargo clippy --version`
+## Logging
+- Use tracing for logging in nginx/apache style.
+- Output goes to stderr for journald/systemd handling.
+- No custom log files or eprintln.