The edit path duplicated the streaming flow with inline require() calls; it now reuses regenerateResponse, which also fixes:
- edited conversations were never saved to History
- the answer generated after an edit could not be stopped (no abort handle kept)
Stopping a stream now saves the partial conversation, like finishing or failing does.
Adds characterization tests for ChatScreen and useLMStudio.
- buildBaseUrl treated any host starting with 'http' (e.g. httpbin.local) as having a scheme
- native streaming finished silently on 4xx/5xx; it now reports the status
- network failures now explain how to fix the connection instead of 'XHR streaming failed: 0'
- testConnection left its 5 s timer running on failure
- SSE parser accepts 'data:' without a space, as the spec allows
evandro