Implement BACKLOG.md items: config-only, request limits, URL validation

- Remove CLI options except --config and --test-processing-delay
- Enforce 1026 byte request limit per Gemini spec (1024 + 2 for CRLF)
- Add comprehensive URL parsing with host and port validation
- Reject malformed URIs and wrong ports with 59 Bad Request
- Update tests for new URL parsing signature
- Fix clippy warning in port parsing

src/server.rs

@@ -41,10 +41,11 @@ pub async fn handle_connection(
     mut stream: TlsStream<TcpStream>,
     dir: &str,
     expected_host: &str,
+    expected_port: u16,
     max_concurrent_requests: usize,
     test_processing_delay: u64,
 ) -> io::Result<()> {
-    const MAX_REQUEST_SIZE: usize = 4096;
+    const MAX_REQUEST_SIZE: usize = 1026;
     const REQUEST_TIMEOUT: Duration = Duration::from_secs(10);
 
     let mut request_buf = Vec::new();
@@ -96,7 +97,7 @@ pub async fn handle_connection(
             }
 
             // Parse Gemini URL
-            let path = match parse_gemini_url(&request, expected_host) {
+            let path = match parse_gemini_url(&request, expected_host, expected_port) {
                 Ok(p) => p,
                 Err(_) => {
                     logger.log_error(59, "Invalid URL format");