fix(ai): disable inputs and show New Chat button on fatal process error

When the Claude process exits with code 1, disable the textarea and
send button, move any queued message back to the textarea, and show
an inline New Chat button. Clicking it starts a fresh session while
preserving the textarea content so the user can re-send.

Author: abose

src/core-ai/AIChatPanel.js

@@ -49,6 +49,7 @@ define(function (require, exports, module) {
     let _currentEdits = [];          // edits in current response, for summary card
     let _firstEditInResponse = true; // tracks first edit per response for initial PUC
     let _undoApplied = false;        // whether undo/restore has been clicked on any card
+    let _sessionError = false;       // set when aiError fires; cleared on new send or new session
     // --- AI event trace logging (compact, non-flooding) ---
     let _traceTextChunks = 0;
     let _traceToolStreamCounts = {}; // toolId → count
@@ -767,6 +768,7 @@ define(function (require, exports, module) {
         $textarea.css("height", "auto");
 
         // Set streaming state
+        _sessionError = false;
         _setStreaming(true);
 
         // Reset segment tracking and show thinking indicator
@@ -870,6 +872,7 @@ define(function (require, exports, module) {
         _segmentText = "";
         _hasReceivedContent = false;
         _isStreaming = false;
+        _sessionError = false;
         _queuedMessage = null;
         _removeQueueBubble();
         _firstEditInResponse = true;
@@ -1260,6 +1263,7 @@ define(function (require, exports, module) {
 
     function _onError(_event, data) {
         console.log("[AI UI]", "Error:", (data.error || "").slice(0, 200));
+        _sessionError = true;
         _appendErrorMessage(data.error);
         // Don't stop streaming — the node side may continue (partial results)
     }
@@ -1279,6 +1283,46 @@ define(function (require, exports, module) {
         SnapshotStore.stopTracking();
         _setStreaming(false);
 
+        // Fatal error (e.g. process exit code 1) — disable inputs, show "New Chat"
+        if (_sessionError && !data.sessionId) {
+            $textarea.prop("disabled", true);
+            $textarea.closest(".ai-chat-input-wrap").addClass("disabled");
+            $sendBtn.prop("disabled", true);
+            // Move queued text back to textarea for user to reuse after new session
+            if (_queuedMessage) {
+                $textarea.val(_queuedMessage.text);
+                _attachedImages = _queuedMessage.images;
+                _renderImagePreview();
+                _queuedMessage = null;
+                _removeQueueBubble();
+            }
+            // Append inline "New Chat" button below the error
+            const $newChat = $(
+                '<div class="ai-msg ai-msg-new-chat">' +
+                    '<button class="ai-error-new-chat-btn">' +
+                        '<i class="fa-solid fa-plus"></i> ' + Strings.AI_CHAT_NEW_BTN +
+                    '</button>' +
+                '</div>'
+            );
+            $newChat.find(".ai-error-new-chat-btn").on("click", function () {
+                // Preserve textarea content and images across the new session
+                const savedText = $textarea.val();
+                const savedImages = _attachedImages.slice();
+                $newChat.remove();
+                _newSession();
+                $textarea.prop("disabled", false);
+                $textarea.closest(".ai-chat-input-wrap").removeClass("disabled");
+                $sendBtn.prop("disabled", false);
+                $textarea.val(savedText);
+                _attachedImages = savedImages;
+                _renderImagePreview();
+                $textarea[0].focus({ preventScroll: true });
+            });
+            $messages.append($newChat);
+            _scrollToBottom();
+            return;
+        }
+
         // If user had a queued message, auto-send it as the next turn
         if (_queuedMessage) {
             const pending = _queuedMessage;

src/styles/Extn-AIChatPanel.less

@@ -942,6 +942,32 @@
     }
 }
 
+/* ── New Chat button after fatal error ─────────────────────────────── */
+.ai-msg-new-chat {
+    display: flex;
+    justify-content: center;
+    padding: 6px 0;
+
+    .ai-error-new-chat-btn {
+        display: flex;
+        align-items: center;
+        gap: 4px;
+        background: none;
+        border: 1px solid rgba(255, 255, 255, 0.12);
+        color: @project-panel-text-2;
+        font-size: @sidebar-small-font-size;
+        padding: 4px 14px;
+        border-radius: 4px;
+        cursor: pointer;
+        transition: background-color 0.15s ease, color 0.15s ease;
+
+        &:hover {
+            background-color: rgba(255, 255, 255, 0.06);
+            color: @project-panel-text-1;
+        }
+    }
+}
+
 /* ── Status bar ─────────────────────────────────────────────────────── */
 .ai-chat-status {
     display: none;