fix(ci): set DISPLAY=:0 for live KDE session

Runner doesn't inherit session env vars - must set explicitly.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <[email protected]>

Author: Coldaine

.github/workflows/ci.yml

@@ -232,7 +232,8 @@ jobs:
     needs: [setup-whisper-dependencies]
     timeout-minutes: 30
     env:
-      # DISPLAY inherited from runner's live KDE session (do NOT hardcode :99)
+      # Runner's live KDE session uses :0 (not :99 which was for Xvfb)
+      DISPLAY: ":0"
       RUST_LOG: debug
       RUST_TEST_TIME_UNIT: 10000
       RUST_TEST_TIME_INTEGRATION: 30000