feat: improve session sharing and Kimi transcript support

- normalize Kimi thinking parts and omit empty placeholders
- add standalone session-sharing and UI demo artifacts
- add regression coverage and refresh the Kimi index marker
- bump the Electron app and CLI packages to v0.2.1
- ignore generated app build assets

app/src/renderer/src/session-timeline-presentation.mjs

@@ -190,7 +190,7 @@ function renderOutput(output, isError) {
   return `<div class="result-chip ${isError ? 'error' : ''}">${escapeHtml(output)}</div>`;
 }
 
-function renderPrettyTool(toolCall) {
+export function renderPrettyTool(toolCall) {
   const args = parseToolInput(toolCall);
   const result = toolCall.result || {};
   const isError = Boolean(result.is_error);