Update the wiki for Mumcord 0.4.3
Point links at the Mumcord organisation
docs: update wiki for 0.4.1 and the upcoming 0.4.2 macOS signing and notarization, keychain and microphone prompts, late-join repeat announcements in the screen share and watch party flows, CI change detection, Dependabot and the apt mirror fallback.
docs(wiki): release v0.3.0 (stages 1c and 1d), privacy and code signing page