feat: add resizable chat input with top drag handle

- Added custom resize handle above textarea that expands upward
- Fixed send button alignment to stay at bottom of textarea
- Replaced native resize with custom drag-to-resize logic
- Height constraints: min 48px, max 200px

src/lib/components/InputBar.svelte

@@ -39,6 +39,37 @@
   let historyIndex = $state(-1);
   let tempInput = $state("");
 
+  // Textarea resize state
+  let textareaHeight = $state(48);
+  const MIN_HEIGHT = 48;
+  const MAX_HEIGHT = 200;
+  let isResizing = $state(false);
+  let startY = 0;
+  let startHeight = 0;
+
+  function handleResizeStart(event: MouseEvent) {
+    isResizing = true;
+    startY = event.clientY;
+    startHeight = textareaHeight;
+    document.addEventListener("mousemove", handleResizeMove);
+    document.addEventListener("mouseup", handleResizeEnd);
+    event.preventDefault();
+  }
+
+  function handleResizeMove(event: MouseEvent) {
+    if (!isResizing) return;
+    // Dragging up (negative deltaY) should increase height
+    const deltaY = startY - event.clientY;
+    const newHeight = Math.min(MAX_HEIGHT, Math.max(MIN_HEIGHT, startHeight + deltaY));
+    textareaHeight = newHeight;
+  }
+
+  function handleResizeEnd() {
+    isResizing = false;
+    document.removeEventListener("mousemove", handleResizeMove);
+    document.removeEventListener("mouseup", handleResizeEnd);
+  }
+
   // Load history from localStorage on init
   function loadHistory(): string[] {
     try {
@@ -314,13 +345,19 @@ User: ${formattedMessage}`;
     <MessageModeSelector />
   </div>
 
-  <div class="input-row flex gap-3 items-end">
-    <div class="flex-1 relative">
+  <div class="input-row">
+    <div class="textarea-wrapper">
       <SlashCommandMenu
         commands={matchingCommands}
         selectedIndex={selectedCommandIndex}
         onSelect={selectCommand}
       />
+      <!-- svelte-ignore a11y_no_static_element_interactions -->
+      <div
+        class="resize-handle"
+        onmousedown={handleResizeStart}
+        title="Drag to resize"
+      ></div>
       <textarea
         bind:value={inputValue}
         onkeydown={handleKeyDown}
@@ -330,41 +367,39 @@ User: ${formattedMessage}`;
           : "Connect to Claude first..."}
         disabled={isSubmitting}
         rows={1}
+        style="height: {textareaHeight}px"
         class="w-full px-4 py-3 bg-[var(--bg-secondary)] border border-[var(--border-color)]
              rounded-lg text-[var(--text-primary)] placeholder-gray-500 resize-none
              focus:outline-none focus:border-[var(--accent-primary)] focus:ring-1 focus:ring-[var(--accent-primary)]
-             disabled:opacity-50 disabled:cursor-not-allowed
-             transition-all duration-200"
+             disabled:opacity-50 disabled:cursor-not-allowed"
       ></textarea>
     </div>
 
-    {#if isProcessing}
-      <button
-        type="button"
-        onclick={handleInterrupt}
-        class="px-6 py-3 bg-red-600 hover:bg-red-700
-             text-white font-medium rounded-lg
-             transition-all duration-200 transform hover:scale-105 active:scale-95"
-        title="Interrupt the current response (Ctrl+C)"
-      >
-        <span class="font-bold">■</span> Stop
-      </button>
-    {:else}
-      <button
-        type="submit"
-        disabled={!isConnected || isSubmitting || !inputValue.trim()}
-        class="px-6 py-3 bg-[var(--accent-primary)] hover:bg-[var(--accent-secondary)]
-             text-white font-medium rounded-lg
-             disabled:opacity-50 disabled:cursor-not-allowed
-             transition-all duration-200 transform hover:scale-105 active:scale-95"
-      >
-        {#if isSubmitting}
-          <span class="inline-block animate-spin">⏳</span>
-        {:else}
-          Send
-        {/if}
-      </button>
-    {/if}
+    <div class="button-wrapper">
+      {#if isProcessing}
+        <button
+          type="button"
+          onclick={handleInterrupt}
+          class="send-button bg-red-600 hover:bg-red-700"
+          title="Interrupt the current response (Ctrl+C)"
+        >
+          <span class="font-bold">■</span> Stop
+        </button>
+      {:else}
+        <button
+          type="submit"
+          disabled={!isConnected || isSubmitting || !inputValue.trim()}
+          class="send-button bg-[var(--accent-primary)] hover:bg-[var(--accent-secondary)]
+               disabled:opacity-50 disabled:cursor-not-allowed"
+        >
+          {#if isSubmitting}
+            <span class="inline-block animate-spin">⏳</span>
+          {:else}
+            Send
+          {/if}
+        </button>
+      {/if}
+    </div>
   </div>
 </form>
 
@@ -386,4 +421,61 @@ User: ${formattedMessage}`;
     gap: 12px;
     align-items: flex-end;
   }
+
+  .textarea-wrapper {
+    flex: 1;
+    position: relative;
+    display: flex;
+    flex-direction: column;
+  }
+
+  .resize-handle {
+    height: 6px;
+    cursor: ns-resize;
+    background: transparent;
+    border-radius: 3px;
+    margin-bottom: 2px;
+    display: flex;
+    justify-content: center;
+    align-items: center;
+  }
+
+  .resize-handle::before {
+    content: "";
+    width: 40px;
+    height: 3px;
+    background: var(--border-color);
+    border-radius: 2px;
+    opacity: 0.5;
+    transition: opacity 0.2s;
+  }
+
+  .resize-handle:hover::before {
+    opacity: 1;
+    background: var(--accent-primary);
+  }
+
+  .button-wrapper {
+    display: flex;
+    align-items: flex-end;
+    height: 100%;
+  }
+
+  .send-button {
+    padding: 0 24px;
+    height: 48px;
+    color: white;
+    font-weight: 500;
+    border-radius: 8px;
+    transition: all 0.2s;
+    white-space: nowrap;
+  }
+
+  .send-button:hover:not(:disabled) {
+    transform: scale(1.05);
+  }
+
+  .send-button:active:not(:disabled) {
+    transform: scale(0.95);
+  }
 </style>