feat(inspector): improve session UI, skills dropdown, and visual polish

- Add delete button on ended sessions (visible on hover)
- Darken ended sessions with opacity and "ended" pill badge
- Sort ended sessions to bottom of list
- Add token usage pill in chat header
- Disable input when session ended
- Add Official Skills dropdown with SDK and Rivet presets
- Format session IDs shorter with full ID on hover
- Add arrow icon to "Configure persistence" link
- Add agent logo SVGs

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

frontend/packages/inspector/src/components/debug/McpTab.tsx

@@ -158,7 +158,7 @@ const McpTab = ({
               value={editJson}
               onChange={(e) => { setEditJson(e.target.value); setEditError(null); }}
               rows={6}
-              style={{ width: "100%", boxSizing: "border-box", fontFamily: "monospace", fontSize: 11 }}
+              style={{ width: "100%", boxSizing: "border-box", fontFamily: "monospace", fontSize: 11, resize: "vertical" }}
             />
             {editError && <div className="banner error" style={{ marginTop: 4 }}>{editError}</div>}
           </div>