[ZhuchkaTriplesix]

Closes #1594, closes #1591. Documentation only.

README → Installation → macOS

• Minimum macOS 10.15, universal build.
• Start the app from Applications: started from the disk image or Downloads it runs as a translocated read-only copy and cannot update itself (fix(updater): macOS in-place update can quit the app and leave a broken bundle #1587).
• Unsigned builds: Control-click → Open on macOS 14 and earlier; System Settings → Privacy & Security → Open Anyway on macOS 15+, where Control-click no longer works; or xattr -dr com.apple.quarantine (only the quarantine flag, instead of the previous xattr -cr, which cleared every attribute).
• The unsigned build is not sandboxed (build(macos): ship the unsigned build without the App Sandbox (ReleaseUnsigned.entitlements) #1592) and behaves like the signed one.

docs/macos-signing.md

• "Running an unsigned build": the same first-launch steps as a table per macOS version, App Translocation, and links to the Keychain (fix(macos): Keychain secrets fail without keychain-access-groups; use the login keychain #1586) and update-signer (fix(updater): verify the signer identity, not just the seal, on macOS updates #1588) changes.
• "Minimum macOS version": MACOSX_DEPLOYMENT_TARGET is 10.15 in every configuration and LSMinimumSystemVersion follows it; that equals the highest plugin minimum (file_selector_macos, url_launcher_macos 10.15; package_info_plus, device_info_plus, refresh_rate 10.14), so the target and the plugins already agree. ProMotion above 60 Hz needs macOS 14 (refresh_rate).

#1591's other task (ship the unsigned build without the sandbox, or document the limitations) was done in #1592; the Step 4 / entitlements contradiction from #1594 was also fixed there, so docs/macos-signing.md already names ReleaseSigned.entitlements for signing.