chore(mac): update setup document

docs/build/macos.md

@@ -28,6 +28,8 @@ The following projects **cannot** be built on macOS:
 ## System Requirements
 
 * Minimum macOS version: macOS Catalina 10.15 or Big Sur 11.0
+(For using Xcode 26.2 or 26.3 macOS Sequoia 15.6 or later is required.
+Make sure bash 4.0 is installed and used as modern macOS defaults to Zsh as its primary system shell)
 
 **Note:** to make a fully M1-compatible release build of Keyman for macOS (for
 the setup Applescript), Big Sur 11.0 is required, as osacompile on earlier
@@ -39,8 +41,9 @@ Rosetta 2 installed.
 
 Many dependencies are only required for specific projects.
 
-* XCode (iOS, macOS) 12.4 or later is needed only for Keyman for macOS and Keyman
-  for iOS.
+* XCode (iOS, macOS) 26.2 or 26.3 (not higher at this time, see #16416) 
+  is needed only for Keyman for macOS and Keyman for iOS ().
+
   * Install from App Store
   * Accept the Xcode license: `sudo xcodebuild -license accept`
 
@@ -105,7 +108,7 @@ PATH="$HOMEBREW_PREFIX/opt/coreutils/libexec/gnubin:$PATH"
 
 ## KeymanWeb Dependencies
 
-* node.js, emscripten 3.1.46 or later
+* node.js 20.0, emscripten 3.1.64
 
 ### node.js
 
@@ -141,7 +144,8 @@ If you are updating an existing install of Emscripten:
 cd emsdk
 git pull
 emsdk install 3.1.58
-emsdk activate 3.1.58
+./emsdk install 3.1.64
+./emsdk activate 3.1.64
 cd upstream/emscripten
 npm install
 ```
@@ -204,7 +208,9 @@ components such as emulator images and SDK updates.
 
 ```shell
 brew install node emscripten
-```
+* node.js 20.0, emscripten 3.1.64
+
+See section KeymanWeb Dependencies for installation
 
 ## Optional Tools