chore(tooling): use ESLint as the sole formatter for TS/Vue files

Disables Prettier in Cursor / VSCode. ESLint via dbaeumer.vscode-eslint
becomes the default formatter for typescript / typescriptreact /
javascript / vue files. Save-on-format runs eslint --fix on the file.

Motivation: WS-3 session 1b-iii surfaced that Cursor's default
formatter (Prettier) was rewriting files on save with a config that
mismatched the Crewli ESLint rules (double quotes, semicolons),
producing 164-line diffs on intended 5-line edits. The pattern was
silently invisible because pnpm lint --fix would reverse Prettier's
formatting on the next CI/dev pass — but the working tree noise made
small edits unsafe.

This commit:
- Updates .vscode/settings.json: editor.defaultFormatter is now
  dbaeumer.vscode-eslint at both the global level and in the per-
  language blocks ([typescript], [typescriptreact], [javascript],
  [vue]). Adds eslint.format.enable, eslint.validate, and
  source.fixAll.eslint to codeActionsOnSave. Sets prettier.enable
  to false explicitly. Preserves pre-existing settings unchanged
  (PHP block, editor.tabSize, typescript.preferences,
  files.associations, search.exclude, eslint.workingDirectories).
- Documents the choice in .cursorrules under a new ## Formatter
  section.

The prior [vue] formatter was Vue.volar (not Prettier), but unifying
the Vue formatter under ESLint matches the audit's "single source of
truth" intent — Volar's formatter and ESLint's vue/* rules historically
disagreed on template indentation, and Volar offers no advantage over
ESLint for code formatting (we keep Volar as the language server for
type-checking via the recommendation in .vscode/extensions.json).

.gitignore did not need updating — .vscode/ was already not ignored
and the existing settings.json was already tracked.

No changes to package.json, pnpm-lock.yaml, .eslintrc.cjs, or any
source files. Engineers using Cursor / VSCode need the
dbaeumer.vscode-eslint extension installed (already present in
.vscode/extensions.json's recommendations).

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

.vscode/settings.json

@@ -1,37 +1,57 @@
 {
   "editor.formatOnSave": true,
   "editor.tabSize": 2,
-  
-  "[php]": {
-    "editor.defaultFormatter": "bmewburn.vscode-intelephense-client",
-    "editor.tabSize": 4
+  "editor.defaultFormatter": "dbaeumer.vscode-eslint",
+  "editor.codeActionsOnSave": {
+    "source.fixAll.eslint": "explicit"
   },
-  
-  "[vue]": {
-    "editor.defaultFormatter": "Vue.volar"
-  },
-  
-  "[typescript]": {
-    "editor.defaultFormatter": "esbenp.prettier-vscode"
-  },
-  
-  "typescript.preferences.importModuleSpecifier": "relative",
-  "typescript.suggest.autoImports": true,
-  
-  "files.associations": {
-    "*.php": "php",
-    ".env*": "dotenv"
-  },
-  
-  "search.exclude": {
-    "**/node_modules": true,
-    "**/vendor": true,
-    "**/dist": true
-  },
-  
+
+  "eslint.format.enable": true,
+  "eslint.validate": [
+    "javascript",
+    "typescript",
+    "vue"
+  ],
   "eslint.workingDirectories": [
     { "directory": "apps/admin", "changeProcessCWD": true },
     { "directory": "apps/app", "changeProcessCWD": true },
     { "directory": "apps/portal", "changeProcessCWD": true }
-  ]
+  ],
+
+  "prettier.enable": false,
+
+  "[php]": {
+    "editor.defaultFormatter": "bmewburn.vscode-intelephense-client",
+    "editor.tabSize": 4
+  },
+
+  "[typescript]": {
+    "editor.defaultFormatter": "dbaeumer.vscode-eslint"
+  },
+
+  "[typescriptreact]": {
+    "editor.defaultFormatter": "dbaeumer.vscode-eslint"
+  },
+
+  "[javascript]": {
+    "editor.defaultFormatter": "dbaeumer.vscode-eslint"
+  },
+
+  "[vue]": {
+    "editor.defaultFormatter": "dbaeumer.vscode-eslint"
+  },
+
+  "typescript.preferences.importModuleSpecifier": "relative",
+  "typescript.suggest.autoImports": true,
+
+  "files.associations": {
+    "*.php": "php",
+    ".env*": "dotenv"
+  },
+
+  "search.exclude": {
+    "**/node_modules": true,
+    "**/vendor": true,
+    "**/dist": true
+  }
 }