Fix achievement icons in launcher, allow opening OAuth URLs, live map docs

- Shared achievement icon catalogue; launcher resolves icon/background/border ids
- Tauri opener capability now allows http(s) URLs (fixes Discord sign-in)
- Rewrite live map docs, admin guide progression section

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01DjMbLQujBHunCCu5GpsHaT

panel/server/tests/progression.rs

@@ -11,7 +11,13 @@ async fn player(t: &TestApp, admin: &str, name: &str) -> (String, String) {
 }
 
 fn ids(v: &Value, period: &str) -> Vec<String> {
-    let mut out: Vec<String> = v.as_array().unwrap().iter().filter(|q| q["quest"]["period"] == period).map(|q| q["quest"]["id"].as_str().unwrap().to_string()).collect();
+    let mut out: Vec<String> = v
+        .as_array()
+        .unwrap()
+        .iter()
+        .filter(|q| q["quest"]["period"] == period)
+        .map(|q| q["quest"]["id"].as_str().unwrap().to_string())
+        .collect();
     out.sort();
     out
 }