fix: deepen opens the linked note, task list columns in "Alle Aufgaben", Whisper repeats, date field

- The deepen buttons of task rows and Kanban cards open an already linked note (accent colour)
  instead of creating another one; the server refuses a second note for a linked task as well.
- "Alle Aufgaben" uses each task's own list columns for the status selector, dot and detail.
- Whisper: send vad_filter (STT_VAD_FILTER, default on) and drop a verbatim repeated tail of
  sentences or words from the transcript.
- Task detail: narrower time field, wider date field in the desktop sidebar.

v0.37.2.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

.env.example

@@ -149,3 +149,5 @@ STT_MAX_PARALLEL=1
 STT_PER_USER_PER_HOUR=60
 # Höchstdauer einer Erkennung in Sekunden, Warten in der Schlange eingeschlossen.
 STT_TIMEOUT_SECONDS=120
+# Bittet den Whisper-Server, Stille zu überspringen (weniger erfundene Wiederholungen); false, falls der Server das Feld ablehnt.
+STT_VAD_FILTER=true