"Flutter Code extension not installed" but it's been installed for months

Have been using Flutter with VSCode on Mac for months without issues, but suddenly flutter doctor produces this:

[✓] Flutter (Channel beta, v0.5.1, on Mac OS X 10.13.4 17E202, locale en-US)
• Flutter version 0.5.1 at [Path]/flutter
• Framework revision c7ea3ca377 (3 weeks ago), 2018-05-29 21:07:33 +0200
• Engine revision 1ed25ca7b7
• Dart version 2.0.0-dev.58.0.flutter-f981f09760

[✓] Android toolchain - develop for Android devices (Android SDK 27.0.3)
• Android SDK at [Path]/Library/Android/sdk
• Android NDK location not configured (optional; useful for native profiling support)
• Platform android-27, build-tools 27.0.3
• Java binary at: /Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/bin/java
• Java version OpenJDK Runtime Environment (build 1.8.0_152-release-1024-b01)
• All Android licenses accepted.

[✓] iOS toolchain - develop for iOS devices (Xcode 9.3.1)
• Xcode at /Applications/Xcode.app/Contents/Developer
• Xcode 9.3.1, Build version 9E501
• ios-deploy 1.9.2
• CocoaPods version 1.5.2

[✓] Android Studio (version 3.1)
• Android Studio at /Applications/Android Studio.app/Contents
• Flutter plugin version 25.0.1
• Dart plugin version 173.4700
• Java version OpenJDK Runtime Environment (build 1.8.0_152-release-1024-b01)

[!] VS Code (version 1.24.1)
• VS Code at /Applications/Visual Studio Code.app/Contents
• Flutter extension not installed; install from
  https://marketplace.visualstudio.com/items?itemName=Dart-Code.flutter

[✓] Connected devices (1 available)
• Android SDK built for x86 • emulator-5554 • android-x86 • Android 9 (API 28) (emulator)

! Doctor found issues in 1 category.

I can confirm that flutter is installed, and nothing has changed since I started using it. Additionally, before I updated flutter (today), flutter doctor read, under VSCode, as:

[!] VS Code (version 1.24.1)
• VS Code at /Applications/Visual Studio Code.app/Contents
• Dart Code extension not installed; install from
  https://marketplace.visualstudio.com/items?itemName=Dart-Code.dart-code

However, post-upgrade that seems the inability to find dart might have been fixed.

There is a post from a few days ago here that indicates flutter doctor may just be inaccurate for the time being, so I tried to run the project, and got the following error stack:

Using hardware rendering with device Android SDK built for x86. 
If you get graphics artifacts, consider enablingsoftware rendering with "--enable-software-rendering".
Launching lib/main.dart on Android SDK built for x86 in debug mode...
Initializing gradle...                                       2.0s
Resolving dependencies...                                    2.2s
Running 'gradlew assembleDebug'...
Error: unable to locate asset entry in pubspec.yaml: 
"ios/Flutter/flutter_assets/fonts/MyFlutterApp.ttf".
Error building assets

FAILURE: Build failed with an exception.

* Where:
Script 
'[Path]/flutter/packages/flutter_tools/gradle/flutter.gradle' line: 435

* What went wrong:
Execution failed for task ':app:flutterBuildDebug'.
> Process 'command 
'[Path]/flutter/bin/flutter'' finished with non-zero exit value 1
* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output.

* Get more help at https://help.gradle.org

BUILD FAILED in 17s
Gradle build failed: 1
MacBook-Pro-3:rambleapp TrentKennelly$ flutter trace
Error connecting to observatory: Exception: Attempted to connect to Dart 
observatory 5 times, and all attempts failed. Giving up. The URL was 
ws://127.0.0.1:8100/ws

Any thoughts on this?