Normalize fingerprints everywhere: strip colons from URLs and DB keys

Client: strip colons before putting fingerprints in URL paths
(colons in URLs confuse axum path matching).

Server: normalize fingerprints in message routes too.

All fingerprint storage and lookup is now hex-only, case-insensitive.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

warzone/crates/warzone-server/src/routes/messages.rs

@@ -21,11 +21,15 @@ struct SendRequest {
     message: Vec<u8>,
 }
 
+fn normalize_fp(fp: &str) -> String {
+    fp.chars().filter(|c| c.is_ascii_hexdigit()).collect::<String>().to_lowercase()
+}
+
 async fn send_message(
     State(state): State<AppState>,
     Json(req): Json<SendRequest>,
 ) -> AppResult<Json<serde_json::Value>> {
-    let key = format!("queue:{}", req.to);
+    let key = format!("queue:{}", normalize_fp(&req.to));
     state.db.messages.insert(
         format!("{}:{}", key, uuid::Uuid::new_v4()).as_bytes(),
         req.message,
@@ -37,7 +41,7 @@ async fn poll_messages(
     State(state): State<AppState>,
     Path(fingerprint): Path<String>,
 ) -> AppResult<Json<Vec<String>>> {
-    let prefix = format!("queue:{}", fingerprint);
+    let prefix = format!("queue:{}", normalize_fp(&fingerprint));
     let mut messages = Vec::new();
     for item in state.db.messages.scan_prefix(prefix.as_bytes()) {
         let (_, value) = item?;