Previously, tapping the mic button would reset the textarea each time,
clobbering anything the user had already typed or previously dictated.
Fix:
- Capture _prefix = ta.value when recording starts (btn.onclick)
- onresult writes _prefix + (final || interim) so live interim text
appears after the existing content, not replacing it
- onend commits _prefix + _finalText with smart space insertion:
if the prefix doesn't end with a space or newline, a space is added
before the new transcript so words don't run together
- _prefix is reset to '' in _setRecording(false) so each new recording
session starts with a fresh snapshot
Behaviour now: tap mic, speak, tap again (or wait for auto-stop) ->
transcript is appended to whatever was in the textarea. Tap mic again
-> continues appending further. Text stays fully editable before send.
tests/test_sprint20.py: 6 new tests covering prefix capture, onresult
prepend, onend commit, reset, and smart spacing (52 total, 382 overall).
46fdf3513f