MuteDeck v4.9.4

Fixes for Teams detection on Windows, Slack huddle controls on macOS, and general stability.

• Teams detection (Windows): No longer drops to "No call" a few minutes into a call. Also works with the redesigned meeting controls in newer Teams versions.
• System slowdown (Windows): 4.9.3 could make other apps — Outlook especially — feel sluggish while looking for Teams. Fixed.
• Teams language mismatch: When Teams is displayed in a different language than the one selected in MuteDeck's settings, you now see "Teams call detected, but Teams appears to be in [language]" instead of a confusing "No call".
• Slack huddles (macOS): Mute clicks could miss Slack's control bar when it was too quick. MuteDeck now verifies the button actually toggled, and a failed attempt no longer yanks your cursor back.
• Hotkeys (macOS): Fixed a leak where hotkey handlers piled up every time settings were saved (memory leak fixed).