fix: Operation Lightspeed review fixes — padding, dead code, tablet WebGL

- Add SSE padding to backpressure drain write for tunnel clients
- Remove dead SessionTerminal from broadcast padding check
- Trim whitespace in SSE session filter query params
- Remove unused _bufferLazyTerminalData scaffolding code
- Skip WebGL on tablets too, not just phones (canvas fallback)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/web/public/app.js

@@ -624,8 +624,8 @@ class CodemanApp {
     // oversized terminal.write() calls that triggered the stalls.
     // Disable with ?nowebgl URL param if GPU issues return.
     this._webglAddon = null;
-    const isMobile = MobileDetection.getDeviceType() === 'mobile';
-    if (!isMobile && !new URLSearchParams(location.search).has('nowebgl') && typeof WebglAddon !== 'undefined') {
+    const skipWebGL = MobileDetection.getDeviceType() !== 'desktop';
+    if (!skipWebGL && !new URLSearchParams(location.search).has('nowebgl') && typeof WebglAddon !== 'undefined') {
       try {
         this._webglAddon = new WebglAddon.WebglAddon();
         this._webglAddon.onContextLoss(() => {
@@ -10157,7 +10157,6 @@ class CodemanApp {
         windowEntry._lazyTerminal = true;
         windowEntry._lazyPaneTarget = paneData.paneTarget;
         windowEntry._lazySessionId = paneData.sessionId;
-        windowEntry._lazyBuffer = '';
       }
     } else {
       this.initTeammateTerminal(windowId, paneData, win);

src/web/public/subagent-windows.js

@@ -471,13 +471,9 @@ Object.assign(CodemanApp.prototype, {
   //   restore  → _restoreTeammateTerminalFromLazy()   → re-creates Terminal
   //   create (hidden/minimized) → skip initTeammateTerminal, set _lazyTerminal
   //
-  // The pane buffer is always re-fetched from the API on restore, so no
-  // client-side buffer accumulation is needed (the tmux pane is the source
-  // of truth). Regular (non-teammate) subagent windows use activity HTML
-  // and are unaffected by this optimization.
-
-  /** Max bytes to buffer for a minimized teammate terminal (256KB). */
-  _LAZY_TERMINAL_BUFFER_CAP: 256 * 1024,
+  // The tmux pane buffer is re-fetched from the API on restore. Regular
+  // (non-teammate) subagent windows use activity HTML and are unaffected
+  // by this optimization.
 
   /**
    * Dispose a teammate terminal when its window is minimized.
@@ -495,8 +491,6 @@ Object.assign(CodemanApp.prototype, {
       windowData._lazyTerminal = true;
       windowData._lazyPaneTarget = termData.paneTarget;
       windowData._lazySessionId = termData.sessionId;
-      // Buffer for any data that arrives while minimized (from pendingData or future writes)
-      windowData._lazyBuffer = '';
     }
 
     // Dispose the resize observer
@@ -532,7 +526,6 @@ Object.assign(CodemanApp.prototype, {
     windowData._lazyTerminal = false;
     windowData._lazyPaneTarget = null;
     windowData._lazySessionId = null;
-    windowData._lazyBuffer = null;
 
     if (!paneTarget || !sessionId) return;
 
@@ -541,29 +534,6 @@ Object.assign(CodemanApp.prototype, {
     this.initTeammateTerminal(agentId, paneInfo, windowData.element);
   },
 
-  /**
-   * Append terminal data to a minimized teammate terminal's lazy buffer.
-   * Called when SSE data arrives for a minimized window. Caps at _LAZY_TERMINAL_BUFFER_CAP.
-   * Returns true if the data was buffered, false if the window is not in lazy mode.
-   */
-  _bufferLazyTerminalData(agentId, data) {
-    const windowData = this.subagentWindows.get(agentId);
-    if (!windowData || !windowData._lazyTerminal) return false;
-
-    if (windowData._lazyBuffer === null || windowData._lazyBuffer === undefined) {
-      windowData._lazyBuffer = '';
-    }
-
-    // Append data, capping total size
-    windowData._lazyBuffer += data;
-    if (windowData._lazyBuffer.length > this._LAZY_TERMINAL_BUFFER_CAP) {
-      // Keep only the tail to stay under cap
-      windowData._lazyBuffer = windowData._lazyBuffer.slice(-this._LAZY_TERMINAL_BUFFER_CAP);
-    }
-
-    return true;
-  },
-
   // ═══════════════════════════════════════════════════════════════
   // Subagent Floating Windows
   // ═══════════════════════════════════════════════════════════════
@@ -809,7 +779,6 @@ Object.assign(CodemanApp.prototype, {
           windowEntry._lazyTerminal = true;
           windowEntry._lazyPaneTarget = paneInfo.paneTarget;
           windowEntry._lazySessionId = paneInfo.sessionId;
-          windowEntry._lazyBuffer = '';
         }
       } else {
         this.initTeammateTerminal(agentId, paneInfo, win);