perf: adaptive polling intervals for frontend (closes #43)

- appDetail: poll every 1s during active deployments, 10s when idle
- deploymentsPage: same adaptive polling for status checks
- Skip fetching container/build logs when panes are not visible
- Use setTimeout chains instead of setInterval for dynamic intervals

static/js/app.js

@@ -185,11 +185,12 @@ document.addEventListener("alpine:init", () => {
     // Track whether user wants auto-scroll (per log pane)
     _containerAutoScroll: true,
     _buildAutoScroll: true,
+    _pollTimer: null,
 
     init() {
       this.deploying = Alpine.store("utils").isDeploying(this.appStatus);
       this.fetchAll();
-      setInterval(() => this.fetchAll(), 1000);
+      this._schedulePoll();
 
       // Set up scroll listeners after DOM is ready
       this.$nextTick(() => {
@@ -198,6 +199,15 @@ document.addEventListener("alpine:init", () => {
       });
     },
 
+    _schedulePoll() {
+      if (this._pollTimer) clearTimeout(this._pollTimer);
+      const interval = Alpine.store("utils").isDeploying(this.appStatus) ? 1000 : 10000;
+      this._pollTimer = setTimeout(() => {
+        this.fetchAll();
+        this._schedulePoll();
+      }, interval);
+    },
+
     _initScrollTracking(el, flag) {
       if (!el) return;
       el.addEventListener('scroll', () => {
@@ -207,18 +217,36 @@ document.addEventListener("alpine:init", () => {
 
     fetchAll() {
       this.fetchAppStatus();
-      this.fetchContainerLogs();
+      // Only fetch logs when the respective pane is visible
-      this.fetchBuildLogs();
+      if (this.$refs.containerLogsWrapper && this._isElementVisible(this.$refs.containerLogsWrapper)) {
+        this.fetchContainerLogs();
+      }
+      if (this.showBuildLogs && this.$refs.buildLogsWrapper && this._isElementVisible(this.$refs.buildLogsWrapper)) {
+        this.fetchBuildLogs();
+      }
       this.fetchRecentDeployments();
     },
 
+    _isElementVisible(el) {
+      if (!el) return false;
+      // Check if element is in viewport (roughly)
+      const rect = el.getBoundingClientRect();
+      return rect.bottom > 0 && rect.top < window.innerHeight;
+    },
+
     async fetchAppStatus() {
       try {
         const res = await fetch(`/apps/${this.appId}/status`);
         const data = await res.json();
+        const wasDeploying = this.deploying;
         this.appStatus = data.status;
         this.deploying = Alpine.store("utils").isDeploying(data.status);
 
+        // Re-schedule polling when deployment state changes
+        if (this.deploying !== wasDeploying) {
+          this._schedulePoll();
+        }
+
         if (
           data.latestDeploymentID &&
           data.latestDeploymentID !== this.currentDeploymentId
@@ -429,7 +457,18 @@ document.addEventListener("alpine:init", () => {
       }
 
       this.fetchAppStatus();
-      setInterval(() => this.fetchAppStatus(), 1000);
+      this._scheduleStatusPoll();
+    },
+
+    _statusPollTimer: null,
+
+    _scheduleStatusPoll() {
+      if (this._statusPollTimer) clearTimeout(this._statusPollTimer);
+      const interval = this.isDeploying ? 1000 : 10000;
+      this._statusPollTimer = setTimeout(() => {
+        this.fetchAppStatus();
+        this._scheduleStatusPoll();
+      }, interval);
     },
 
     async fetchAppStatus() {
@@ -464,6 +503,7 @@ document.addEventListener("alpine:init", () => {
         // Update deploying state based on latest deployment status
         if (deploying && !this.isDeploying) {
           this.isDeploying = true;
+          this._scheduleStatusPoll(); // Switch to fast polling
         } else if (!deploying && this.isDeploying) {
           // Deployment finished - reload to show final state
           this.isDeploying = false;