feat: add URL parameter syncing for session and player

Implement URL search parameter synchronization for `session` and
`player`
to allow for bookmarkable links. Added `sessionName` to the journal
stream state to support displaying human-readable session names in the
UI. Improved layout transitions and updated the JournalPanel to show
more detailed connection information.

src/App.tsx

@@ -114,8 +114,11 @@ const App: Component = () => {
           </button>
         </div>
       </header>
-      {/* fill th rest of the space*/}
-      <div class="fixed top-16 left-0 right-0 bottom-0 overflow-auto">
+      {/* fill the rest of the space */}
+      <div
+        class="fixed top-16 left-0 right-0 bottom-0 overflow-auto transition-all duration-300"
+        classList={{ "md:pr-[420px]": isJournalOpen() }}
+      >
         <main class="max-w-4xl mx-auto px-4 py-8 pt-4 md:ml-64 2xl:ml-auto flex justify-center items-center">
           <Article
             class="prose text-black prose-sm max-w-full flex-1"

src/components/journal/ConnectionBar.tsx

@@ -10,6 +10,7 @@ import {
   createSession,
   deleteSession,
   disconnectStream,
+  setSessionId,
 } from "../stores/journalStream";
 import { journalSetState } from "../stores/journalStream";
 
@@ -38,7 +39,7 @@ export const ConnectionBar: Component = () => {
   const handleSessionSelect = async (id: string) => {
     try {
       await hydrateFromServer(id);
-      journalSetState("sessionId", id);
+      setSessionId(id);
     } catch (e) {
       setError("Failed to load session");
     }
@@ -56,7 +57,7 @@ export const ConnectionBar: Component = () => {
         <span class="text-xs text-gray-500">connected</span>
         <Show when={stream.sessionId}>
           <span class="text-xs font-mono bg-gray-100 px-1.5 py-0.5 rounded">
-            {stream.sessionId}
+            {stream.sessionName || stream.sessionId}
           </span>
         </Show>
         <div class="flex-1" />

src/components/journal/JournalPanel.tsx

@@ -11,6 +11,7 @@ import {
   hydrateFromServer,
   useJournalStream,
   setMyName,
+  setSessionId,
 } from "../stores/journalStream";
 import { ConnectionBar } from "./ConnectionBar";
 import { StreamView } from "./StreamView";
@@ -26,9 +27,9 @@ export const JournalPanel: Component<JournalPanelProps> = (props) => {
 
   return (
     <>
-      {/* Backdrop — hidden on desktop since panel doesn't overlay content */}
+      {/* Backdrop — only on mobile, starts below header */}
       <div
-        class="fixed inset-0 bg-black/30 z-40 md:hidden"
+        class="fixed top-16 inset-x-0 bottom-0 bg-black/30 z-40 md:hidden"
         classList={{ hidden: !props.open }}
         onClick={props.onClose}
       />
@@ -43,10 +44,9 @@ export const JournalPanel: Component<JournalPanelProps> = (props) => {
       >
         {/* Header */}
         <div class="flex items-center justify-between px-3 py-2 border-b border-gray-200 shrink-0">
-          <div class="flex items-center gap-2">
-            <h2 class="text-sm font-semibold text-gray-700">Journal</h2>
+          <div class="flex items-center gap-2 min-w-0">
             <span
-              class="w-2 h-2 rounded-full"
+              class="w-2 h-2 rounded-full shrink-0"
               classList={{
                 "bg-gray-400": stream.connectionStatus === "disconnected",
                 "bg-yellow-400 animate-pulse":
@@ -56,10 +56,27 @@ export const JournalPanel: Component<JournalPanelProps> = (props) => {
               }}
               title={stream.connectionStatus}
             />
+            <Show
+              when={stream.connected && stream.sessionId}
+              fallback={
+                <h2 class="text-sm font-semibold text-gray-700 truncate">
+                  Disconnected
+                </h2>
+              }
+            >
+              <div class="min-w-0">
+                <p class="text-sm font-semibold text-gray-700 truncate leading-tight">
+                  {stream.myName}
+                </p>
+                <p class="text-[10px] text-gray-400 truncate leading-tight">
+                  {stream.sessionName || stream.sessionId}
+                </p>
+              </div>
+            </Show>
           </div>
           <button
             onClick={props.onClose}
-            class="text-gray-400 hover:text-gray-600 text-sm px-1"
+            class="text-gray-400 hover:text-gray-600 text-sm px-1 shrink-0"
             title="Hide panel"
           >
             ▸
@@ -114,6 +131,7 @@ const ConnectDialog: Component = () => {
     try {
       setMyName(name);
       const sessionId = stream.sessionId || "default";
+      setSessionId(sessionId);
       await hydrateFromServer(sessionId);
       await connectStream(sessionId, brokerUrl);
     } catch (e) {

src/components/stores/journalStream.ts

@@ -22,6 +22,8 @@ import { getMessageType, validatePayload } from "../journal/registry";
 
 export interface JournalStreamState {
   sessionId: string | null;
+  /** Human-readable name for the current session (from manifest) */
+  sessionName: string | null;
   /** Full message log, oldest-first */
   messages: StreamMessage[];
   /** Last sequence number per sender */
@@ -81,19 +83,30 @@ function loadPersisted(): {
 // ---------------------------------------------------------------------------
 
 const persisted = loadPersisted();
+const urlParams = readUrlParams();
+
+// URL params override localStorage if present
+const initialName = urlParams.playerName ?? persisted.myName;
+const initialSession = urlParams.sessionId ?? persisted.lastSessionId;
 
 const [state, setState] = createStore<JournalStreamState>({
-  sessionId: persisted.lastSessionId,
+  sessionId: initialSession,
+  sessionName: null,
   messages: [],
   senderSeq: {},
   revealedPaths: new Set(),
   connected: false,
   connectionStatus: "disconnected",
   connectionError: null,
-  myName: persisted.myName,
+  myName: initialName,
   brokerUrl: persisted.brokerUrl,
 });
 
+// Sync initial URL params if they came from localStorage (not URL)
+if (initialName && !urlParams.playerName) syncUrlParam("player", initialName);
+if (initialSession && !urlParams.sessionId)
+  syncUrlParam("session", initialSession);
+
 export { setState as journalSetState };
 
 const [sessionList, setSessionList] = createSignal<SessionManifest>({
@@ -104,13 +117,70 @@ export { sessionList as sessions };
 
 /**
  * Change the current player's name. Persisted to localStorage so it
- * survives page reloads.
+ * survives page reloads. Also syncs to URL search param.
  */
 export function setMyName(name: string): void {
   setState("myName", name);
   if (typeof localStorage !== "undefined") {
     localStorage.setItem(LS_PLAYER_NAME, name);
   }
+  syncUrlParam("player", name);
+}
+
+/**
+ * Set the active session ID and sync to URL. Also resolves the human-readable
+ * session name from the cached manifest.
+ */
+export function setSessionId(id: string | null): void {
+  setState("sessionId", id);
+  if (typeof localStorage !== "undefined" && id) {
+    localStorage.setItem(LS_LAST_SESSION, id);
+  }
+  if (id) {
+    syncUrlParam("session", id);
+    // Resolve session name from current manifest
+    const manifest = sessionList();
+    const name = manifest.sessions[id]?.name ?? null;
+    setState("sessionName", name);
+  } else {
+    removeUrlParam("session");
+    setState("sessionName", null);
+  }
+}
+
+// ---------------------------------------------------------------------------
+// URL param sync (session & player for bookmarkable links)
+// ---------------------------------------------------------------------------
+
+function syncUrlParam(key: string, value: string): void {
+  if (typeof window === "undefined") return;
+  const url = new URL(window.location.href);
+  url.searchParams.set(key, value);
+  window.history.replaceState(null, "", url.toString());
+}
+
+function removeUrlParam(key: string): void {
+  if (typeof window === "undefined") return;
+  const url = new URL(window.location.href);
+  url.searchParams.delete(key);
+  window.history.replaceState(null, "", url.toString());
+}
+
+/**
+ * Read initial session/player from URL search params on store init.
+ * Called once at module load time.
+ */
+function readUrlParams(): {
+  sessionId: string | null;
+  playerName: string | null;
+} {
+  if (typeof window === "undefined")
+    return { sessionId: null, playerName: null };
+  const params = new URL(window.location.href).searchParams;
+  return {
+    sessionId: params.get("session"),
+    playerName: params.get("player"),
+  };
 }
 
 // Will hold the MQTT client instance after connect()
@@ -253,6 +323,11 @@ export async function connectStream(
         try {
           const manifest: SessionManifest = JSON.parse(raw);
           setSessionList(manifest);
+          // Refresh the sessionName if we're in a session now
+          const currentId = state.sessionId;
+          if (currentId && manifest.sessions[currentId]) {
+            setState("sessionName", manifest.sessions[currentId].name);
+          }
         } catch (e) {
           console.error("[stream] manifest parse err:", e);
         }