v1.91.160.0 fix(scope,review,ship): recognise Dart and Flutter in diff scope and test detection (#3284) (#3300)

* fix(scope,review,ship): recognise Dart and Flutter in diff scope and test detection (#3284)

Port of arlophoenix's #3284 onto current main, squashed:
- gstack-diff-scope: .dart is frontend and backend; pubspec.lock is config.
- lib/frontend-scope.ts mirrors the frontend half; gstack-design-detect
  never sends .dart to the impeccable engine.
- Test bootstrap, coverage audits and review-army detect Dart/Flutter
  (RUNTIME:dart, FRAMEWORK:flutter, dart_test.yaml, *_test.dart).
- Adversarial DIFF_SIZE sums git diff --numstat.

On top of the contributor's diff: shorten the bootstrap's ecosystem-marker
comment so /design-review stays at its SKILL.md size pin, lower the 31 pins
that shrank, and add the CHANGELOG entry.

Co-authored-by: arlophoenix <arlo.phoenix@gmail.com>
Co-authored-by: capy-ai[bot] <230910855+capy-ai[bot]@users.noreply.github.com>

* v1.91.160.0 fix(scope,review,ship): recognise Dart and Flutter in diff scope and test detection (#3300)

Co-authored-by: capy-ai[bot] <230910855+capy-ai[bot]@users.noreply.github.com>

---------

Co-authored-by: arlophoenix <arlo.phoenix@gmail.com>
Co-authored-by: capy-ai[bot] <230910855+capy-ai[bot]@users.noreply.github.com>

bin/gstack-diff-scope

@@ -104,6 +104,11 @@ for f in ${FILES_LIST[@]+"${FILES_LIST[@]}"}; do
     *.tsx|*.jsx|*.vue|*.svelte|*.astro) m_frontend=true ;;
     *.erb|*.haml|*.slim|*.hbs|*.ejs) m_frontend=true ;;
     *.html) m_frontend=true ;;
+    # Dart: the extension cannot tell a Flutter widget from a repository or a
+    # pure-Dart server, so it is BOTH frontend and backend (BACKEND set below).
+    # A skipped reviewer is invisible; an extra one (design-lite included) is a
+    # visible pass that costs a review.
+    *.dart) m_frontend=true ;;
     tailwind.config.*|postcss.config.*) m_frontend=true ;;
     app/views/*|*/components/*|styles/*|css/*|app/assets/stylesheets/*) m_frontend=true ;;
   esac
@@ -135,6 +140,7 @@ for f in ${FILES_LIST[@]+"${FILES_LIST[@]}"}; do
     *.yml|*.yaml) m_config=true ;;
     .github/*) m_config=true ;;
     requirements.txt|pyproject.toml|go.mod|Cargo.toml|composer.json) m_config=true ;;
+    pubspec.lock|*/pubspec.lock) m_config=true ;;
   esac
 
   # Migrations: database migration files. Bare migrations/* covers a
@@ -169,6 +175,9 @@ for f in ${FILES_LIST[@]+"${FILES_LIST[@]}"}; do
       *.ts|*.js|*.mjs|*.cjs|*.mts|*.cts) m_backend=true ;;
     esac
   fi
+  case "$f" in
+    *.dart) m_backend=true ;;
+  esac
 
   [ "$m_frontend" = true ] && FRONTEND=true
   [ "$m_prompts" = true ] && PROMPTS=true