fix(fe): perbaiki infinite loop dashboard, config fetching, infinite scroll, dan visualizer reactivity

- Dashboard: ganti Effect::new dengan spawn_local untuk initial fetch agar
  tidak terjadi infinite loop karena reactive dependency tracking
- Config: tambah api/config.rs dan jadikan AppConfig.monitor_guild_id
  RwSignal supaya di-fetch dari backend (saat startup & setelah login)
- Messages: perbaiki messageFetch agar guild_id terbaca dari config reaktif
- Infinite scroll: tambah observer_ready signal + spawn_local trigger
  agar IntersectionObserver setup setelah DOM mount; tambah fallback button
- AudioVisualizer & MicLevelMeter: tambah periodic tick signal (100ms)
  agar efek re-run dan update bars/level dari shared PCM buffer
- pcm_decoder: ganti js_sys::eval dengan wasm-bindgen binding langsung ke btoa

services/frontend/frontend/src/api/config.rs

@@ -0,0 +1,13 @@
+use crate::api::client::{request, ApiError};
+use serde::Deserialize;
+
+#[derive(Debug, Clone, Deserialize)]
+#[serde(rename_all = "camelCase")]
+pub struct AppConfigResponse {
+    pub monitor_guild_id: Option<String>,
+}
+
+/// GET /api/config
+pub async fn get_config() -> Result<AppConfigResponse, ApiError> {
+    request("GET", "/api/config", None).await
+}

services/frontend/frontend/src/api/mod.rs

@@ -1,5 +1,6 @@
 pub mod auth;
 pub mod client;
+pub mod config;
 pub mod dashboard;
 pub mod mascot;
 pub mod messages;

services/frontend/frontend/src/app.rs

@@ -1,3 +1,4 @@
+use crate::api::config as config_api;
 use crate::features::dashboard::DashboardPanel;
 use crate::features::live::LivePanel;
 use crate::features::messages::MessagesPanel;
@@ -6,6 +7,7 @@ use crate::features::polish::{initial_theme, ThemeContext};
 use crate::ws::context::WsContext;
 use leptos::prelude::*;
 use shared_types::ui_state::Tab;
+use wasm_bindgen_futures::spawn_local;
 
 /// Derive WebSocket URL from the page's own origin.
 /// In development (serve on :8080, backend on :3001) use the detected host + /ws path.
@@ -28,7 +30,7 @@ fn get_ws_url() -> String {
 
 #[derive(Clone)]
 pub struct AppConfig {
-    pub monitor_guild_id: Option<String>,
+    pub monitor_guild_id: RwSignal<Option<String>>,
 }
 
 // ── Contexts ────────────────────────────────────────────
@@ -67,15 +69,53 @@ pub fn App() -> impl IntoView {
     provide_context(theme.clone());
 
     let config = AppConfig {
-        monitor_guild_id: None,
+        monitor_guild_id: RwSignal::new(None),
     };
-    provide_context(config);
+    provide_context(config.clone());
 
     let ws = WsContext::new(&get_ws_url());
     provide_context(ws.clone());
 
     ws.connect();
 
+    // Try to fetch config on startup (works if password is already in localStorage)
+    spawn_local({
+        let config = config.clone();
+        async move {
+            match config_api::get_config().await {
+                Ok(cfg) => {
+                    config.monitor_guild_id.set(cfg.monitor_guild_id);
+                }
+                Err(e) => {
+                    web_sys::console::log_1(
+                        &format!("[config] failed to fetch: {}", e).into(),
+                    );
+                }
+            }
+        }
+    });
+
+    // Re-fetch config when user authenticates (handles first-time login)
+    Effect::new(move |_| {
+        if auth.authenticated.get() {
+            spawn_local({
+                let config = config.clone();
+                async move {
+                    match config_api::get_config().await {
+                        Ok(cfg) => {
+                            config.monitor_guild_id.set(cfg.monitor_guild_id);
+                        }
+                        Err(e) => {
+                            web_sys::console::log_1(
+                                &format!("[config] fetch after auth failed: {}", e).into(),
+                            );
+                        }
+                    }
+                }
+            });
+        }
+    });
+
     view! {
         <div data-theme=move || theme.theme.get()>
             <ParticleBackground />

services/frontend/frontend/src/features/dashboard/mod.rs

@@ -114,11 +114,12 @@ pub fn DashboardPanel() -> impl IntoView {
         });
     });
 
+    // Initial fetch on mount (use spawn_local to avoid reactive dependency tracking)
     {
         let fetch_stats = fetch_stats.clone();
         let fetch_users = fetch_users.clone();
         let fetch_channels = fetch_channels.clone();
-        Effect::new(move |_| {
+        spawn_local(async move {
             fetch_stats();
             fetch_users(true);
             fetch_channels(true);

services/frontend/frontend/src/features/live/audio/pcm_decoder.rs

@@ -1,3 +1,5 @@
+use wasm_bindgen::prelude::*;
+
 /// PCM Frame decoded from binary WebSocket data
 /// Format: [u32 userId (4 bytes)][i16 samples (N bytes)]
 pub struct PcmFrame {
@@ -53,15 +55,16 @@ pub fn encode_samples_to_base64(samples: &[f32]) -> String {
     encode_bytes_base64(&bytes)
 }
 
-/// Encode raw bytes to base64 using JavaScript's btoa
+/// Encode raw bytes to base64 using JavaScript's btoa via wasm-bindgen
 fn encode_bytes_base64(data: &[u8]) -> String {
-    // Build binary string for btoa
-    let binary: String = data.iter().map(|&b| b as char).collect();
+    // Convert bytes 0-255 to a Latin-1 string (each byte → char with same codepoint)
+    let latin1: String = data.iter().map(|&b| b as char).collect();
+    js_btoa(&latin1)
+}
 
-    // Call btoa from JavaScript via js_sys::eval
-    let js_code = format!("btoa('{}')", binary.replace('\'', "\\'"));
-    js_sys::eval(&js_code)
-        .ok()
-        .and_then(|r| r.as_string())
-        .unwrap_or_default()
+/// Direct wasm-bindgen binding to the browser's btoa function
+#[wasm_bindgen]
+extern "C" {
+    #[wasm_bindgen(js_name = btoa)]
+    fn js_btoa(input: &str) -> String;
 }

services/frontend/frontend/src/features/live/components/audio_visualizer.rs

@@ -9,9 +9,19 @@ pub fn AudioVisualizer(
     #[prop(optional)] pcm_data: Option<Arc<Mutex<Vec<f32>>>>,
 ) -> impl IntoView {
     let bars = RwSignal::new(vec![0.0; 32]);
+    let (tick, set_tick) = signal(0u32);
 
-    // Periodically update bars from PCM data
+    // Drive periodic updates: increment tick every 100ms
+    wasm_bindgen_futures::spawn_local(async move {
+        loop {
+            gloo_timers::future::TimeoutFuture::new(100).await;
+            set_tick.update(|t| *t = t.wrapping_add(1));
+        }
+    });
+
+    // Effect reacts to tick changes, updating bars from PCM data each frame
     Effect::new(move |_| {
+        tick.get(); // Track — Effect re-runs on each tick (every 100ms)
         if let Some(ref pcm_arc) = pcm_data {
             if let Ok(pcm_vec) = pcm_arc.lock() {
                 let computed = compute_frequency_bands(&pcm_vec);

services/frontend/frontend/src/features/live/components/mic_level_meter.rs

@@ -11,9 +11,19 @@ pub fn MicLevelMeter(
 ) -> impl IntoView {
     let level = RwSignal::new(0.0f32);
     let peak = RwSignal::new(0.0f32);
+    let (tick, set_tick) = signal(0u32);
 
-    // Update level periodically
+    // Drive periodic updates: increment tick every 100ms
+    wasm_bindgen_futures::spawn_local(async move {
+        loop {
+            gloo_timers::future::TimeoutFuture::new(100).await;
+            set_tick.update(|t| *t = t.wrapping_add(1));
+        }
+    });
+
+    // Effect reacts to tick changes, updating level from PCM data each frame
     Effect::new(move |_| {
+        tick.get(); // Track — Effect re-runs on each tick
         if !active {
             return;
         }

services/frontend/frontend/src/features/messages/components/message_feed.rs

@@ -3,6 +3,7 @@ use leptos::prelude::*;
 use shared_types::message::MessageRecord;
 use std::sync::Arc;
 use wasm_bindgen::prelude::*;
+use wasm_bindgen::JsCast;
 use web_sys::IntersectionObserver;
 
 const GROUP_WINDOW_MS: i64 = 5 * 60 * 1000;
@@ -40,31 +41,52 @@ pub fn MessageFeed(
     on_reanalyze: Arc<dyn Fn(String) + Send + Sync + 'static>,
 ) -> impl IntoView {
     let sentinel_ref = NodeRef::<html::Div>::new();
-    let (_intersecting, _set_intersecting) = signal(false);
+    let (observer_ready, set_observer_ready) = signal(false);
 
+    // Schedule observer setup to run AFTER the DOM is mounted (next microtask).
+    // With has_more, !loading, and messages present the sentinel div will be in the DOM.
+    if !loading && !messages.is_empty() && has_more {
+        wasm_bindgen_futures::spawn_local({
+            let setter = set_observer_ready;
+            async move {
+                setter.set(true);
+            }
+        });
+    }
+
+    // Clone before move into Effect closure so it's still available for the view
+    let on_load_more_io = on_load_more.clone();
     Effect::new(move |_| {
-        let _ = _intersecting.get(); // track signal
+        let _ready = observer_ready.get();
+        if !_ready {
+            return;
+        }
         if let Some(node) = sentinel_ref.get() {
-            let on_load_more = on_load_more.clone();
-            let cb = Closure::<dyn Fn(Vec<JsValue>)>::new(move |entries: Vec<JsValue>| {
-                for entry in entries {
-                    if let Some(entry) = entry.dyn_ref::<web_sys::IntersectionObserverEntry>() {
-                        if entry.is_intersecting() {
-                            if let Some(ref cb) = on_load_more {
-                                cb();
+            let cb = on_load_more_io.clone();
+            let observer_cb = Closure::<dyn Fn(Vec<JsValue>, IntersectionObserver)>::new(
+                move |entries: Vec<JsValue>, _observer: IntersectionObserver| {
+                    for entry in entries {
+                        if let Some(entry) =
+                            entry.dyn_ref::<web_sys::IntersectionObserverEntry>()
+                        {
+                            if entry.is_intersecting() {
+                                if let Some(ref cb) = cb {
+                                    cb();
+                                }
                             }
                         }
                     }
-                }
-            });
-            let observer = IntersectionObserver::new(cb.as_ref().unchecked_ref())
-                .expect("IntersectionObserver failed");
+                },
+            );
+            let observer =
+                IntersectionObserver::new(observer_cb.as_ref().unchecked_ref())
+                    .expect("IntersectionObserver failed");
             observer.observe(&node);
+            // Keep closure alive — forget rather than cleanup since observer owns it
+            observer_cb.forget();
             on_cleanup(move || {
                 observer.disconnect();
             });
-            // Keep closure alive
-            cb.forget();
         }
     });
 
@@ -105,15 +127,33 @@ pub fn MessageFeed(
                 }
             }).collect::<Vec<_>>()}
 
-            {/* Infinite scroll sentinel */}
+            {/* Infinite scroll sentinel + fallback load more button */}
             {has_more_val.then(|| {
                 view! {
-                    <div node_ref=sentinel_ref class="h-4">
-                        {loading_more_val.then(|| {
-                            use super::message_card::MessageCardSkeleton;
-                            view! { <MessageCardSkeleton /> }
+                    <>
+                        <div node_ref=sentinel_ref class="h-4">
+                            {loading_more_val.then(|| {
+                                use super::message_card::MessageCardSkeleton;
+                                view! { <MessageCardSkeleton /> }
+                            })}
+                        </div>
+                        {/* Fallback: visible button in case IntersectionObserver doesn't fire */}
+                        {(!loading_more_val).then(|| {
+                            let load_more_cb = on_load_more.clone();
+                            view! {
+                                <div class="mt-4 text-center">
+                                    <button
+                                        class="btn btn-outline btn-sm"
+                                        on:click=move |_| {
+                                            if let Some(ref cb) = load_more_cb { cb(); }
+                                        }
+                                    >
+                                        "Load more"
+                                    </button>
+                                </div>
+                            }
                         })}
-                    </div>
+                    </>
                 }
             })}
         </div>

services/frontend/frontend/src/features/messages/mod.rs

@@ -164,8 +164,9 @@ pub fn MessagesPanel() -> impl IntoView {
     // Fetch messages on mount if guild is configured
     Effect::new(move |_| {
         if let Some(config) = use_context::<crate::app::AppConfig>() {
-            if let Some(ref guild_id) = config.monitor_guild_id {
-                (state.fetch_messages)(guild_id.clone());
+            if let Some(ref guild_id) = config.monitor_guild_id.get() {
+                let gid = guild_id.clone();
+                (state.fetch_messages)(gid);
             }
         }
     });

services/frontend/frontend/src/ui/toast.rs

@@ -52,7 +52,7 @@ impl ToastContext {
 
         // Auto-dismiss after 4 seconds
         let toasts = self.toasts;
-        leptos::prelude::set_timeout(
+        let _ = leptos::prelude::set_timeout(
             move || {
                 toasts.update(|t| t.retain(|m| m.id != id));
             },