Capture the actual input/output token counts from Cursor API's finish
event (messageMetadata.usage) and use them in place of tiktoken
estimates where available. Fall back to tiktoken if not present.
- src/types.ts: extend CursorSSEEvent with finishReason/messageMetadata
- src/handler.ts: capture finish event usage in streaming paths, pass
real counts to updateSummary with tiktoken fallback
- src/logger.ts: add inputTokens/outputTokens fields to RequestSummary
- vue-ui: show ↑/↓ Cursor tokens in RequestList, DetailPanel, PayloadView
- public/logs.js: show ↑/↓ Cursor tokens in scard and prompts summary
