Move tool notifications to status bar, add UI improvements

- Tool calls now display in status bar instead of chat messages
- Added "working" status style (blue, italic)
- Added floating draggable button as UI fallback
- Added Stop, Copy, Save, Clear buttons
- Added markdown rendering for assistant messages
- Improved session handling and abort support

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

styles/gm-assistant.css

@@ -44,6 +44,72 @@
 .gm-assistant-message.assistant {
   background: var(--color-bg-btn);
   margin-right: auto;
+  max-width: 100%;
+}
+
+/* Markdown styles for assistant messages */
+.gm-assistant-message.assistant h2 {
+  font-size: 1.2em;
+  margin: 0.5em 0 0.3em;
+  border-bottom: 1px solid var(--color-border-light);
+}
+
+.gm-assistant-message.assistant h3 {
+  font-size: 1.1em;
+  margin: 0.5em 0 0.3em;
+}
+
+.gm-assistant-message.assistant h4 {
+  font-size: 1em;
+  margin: 0.4em 0 0.2em;
+}
+
+.gm-assistant-message.assistant strong {
+  color: var(--color-text-light-highlight);
+}
+
+.gm-assistant-message.assistant code {
+  background: rgba(0, 0, 0, 0.2);
+  padding: 1px 4px;
+  border-radius: 3px;
+  font-family: monospace;
+  font-size: 0.9em;
+}
+
+.gm-assistant-message.assistant pre {
+  background: rgba(0, 0, 0, 0.2);
+  padding: 8px;
+  border-radius: 4px;
+  overflow-x: auto;
+  margin: 0.5em 0;
+}
+
+.gm-assistant-message.assistant pre code {
+  background: none;
+  padding: 0;
+}
+
+.gm-assistant-message.assistant blockquote {
+  border-left: 3px solid var(--color-warm-1);
+  margin: 0.5em 0;
+  padding-left: 10px;
+  font-style: italic;
+  color: var(--color-text-light-secondary);
+}
+
+.gm-assistant-message.assistant ul {
+  margin: 0.3em 0;
+  padding-left: 1.5em;
+}
+
+.gm-assistant-message.assistant li {
+  margin: 0.2em 0;
+}
+
+.gm-assistant-message.assistant hr {
+  border: none;
+  border-top: 1px solid var(--color-border-light);
+  margin: 0.5em 0;
 }
 
 .gm-assistant-message.system {
@@ -98,6 +164,10 @@
   font-size: 0.85em;
 }
 
+.gm-assistant-input-area button.save {
+  background: var(--color-cool-3);
+}
+
 /* Status bar */
 .gm-assistant-status {
   padding: 5px 10px;
@@ -115,6 +185,11 @@
   color: #f44336;
 }
 
+.gm-assistant-status.working {
+  color: #64b5f6;
+  font-style: italic;
+}
+
 /* Typing indicator */
 .gm-assistant-typing {
   display: flex;