chore: migrate to Biome for lint and format via Ultracite, remove ESLint Prettier and Stylelint, trim overrides and lockfile, reformat app and server code, update VS Code Cursor hooks and AGENTS

Author: Coinnich

.cursor/hooks.json

@@ -4,6 +4,9 @@
     "afterFileEdit": [
       {
         "command": "bun fix"
+      },
+      {
+        "command": "bun fix --skip=correctness/noUnusedImports"
       }
     ]
   }

.fallowrc.json

@@ -1,6 +1,6 @@
 {
   "$schema": "https://raw.githubusercontent.com/fallow-rs/fallow/main/schema.json",
-  "ignoreDependencies": ["@varlock/bitwarden-plugin"],
+  "ignoreDependencies": ["@varlock/bitwarden-plugin", "@sveltejs/mcp"],
   "rules": {
     "boundary-violation": "warn"
   },

.prettierignore

@@ -1,26 +1,13 @@
 {
-  "editor.defaultFormatter": "esbenp.prettier-vscode",
+  "editor.defaultFormatter": "biomejs.biome",
   "editor.formatOnSave": true,
   "editor.codeActionsOnSave": {
-    "source.fixAll.eslint": "explicit",
-    "source.organizeImports": "explicit"
+    "source.fixAll.biome": "explicit"
   },
   "editor.tabSize": 2,
   "editor.insertSpaces": true,
   "editor.detectIndentation": false,
   "editor.autoIndent": "full",
-  "eslint.validate": [
-    "javascript",
-    "javascriptreact",
-    "typescript",
-    "typescriptreact",
-    "svelte"
-  ],
-  "eslint.workingDirectories": ["."],
-  "eslint.format.enable": true,
-  "prettier.documentSelectors": [
-    "**/*.{js,jsx,ts,tsx,svelte,css,html,json,md}"
-  ],
   "css.validate": false,
   "less.validate": false,
   "scss.validate": false,
@@ -37,27 +24,55 @@
   },
   "typescript.preferences.autoImportSpecifierExcludeRegexes": ["^(node:)?os$"],
   "[typescript]": {
-    "editor.defaultFormatter": "esbenp.prettier-vscode"
+    "editor.defaultFormatter": "biomejs.biome"
   },
   "[jsonc]": {
-    "editor.defaultFormatter": "esbenp.prettier-vscode"
+    "editor.defaultFormatter": "biomejs.biome"
   },
   "typescript.tsdk": "node_modules/typescript/lib",
   "[json]": {
-    "editor.defaultFormatter": "esbenp.prettier-vscode"
+    "editor.defaultFormatter": "biomejs.biome"
   },
   "[tailwindcss]": {
-    "editor.defaultFormatter": "esbenp.prettier-vscode"
+    "editor.defaultFormatter": "biomejs.biome"
   },
   "files.associations": {
     "*.css": "tailwindcss"
   },
   "editor.formatOnPaste": true,
   "emmet.showExpandedAbbreviation": "never",
   "markdown.validate.enabled": true,
-  "js/ts.tsdk.path": "node_modules/typescript/lib",
-  "js/ts.tsdk.promptToUseWorkspaceVersion": true,
   "[svelte]": {
-    "editor.defaultFormatter": "esbenp.prettier-vscode"
+    "editor.defaultFormatter": "svelte.svelte-vscode"
+  },
+  "[css]": {
+    "editor.defaultFormatter": "biomejs.biome"
+  },
+  "[graphql]": {
+    "editor.defaultFormatter": "biomejs.biome"
+  },
+  "[html]": {
+    "editor.defaultFormatter": "biomejs.biome"
+  },
+  "[javascript]": {
+    "editor.defaultFormatter": "biomejs.biome"
+  },
+  "[javascriptreact]": {
+    "editor.defaultFormatter": "biomejs.biome"
+  },
+  "[markdown]": {
+    "editor.defaultFormatter": "biomejs.biome"
+  },
+  "[mdx]": {
+    "editor.defaultFormatter": "biomejs.biome"
+  },
+  "[typescriptreact]": {
+    "editor.defaultFormatter": "biomejs.biome"
+  },
+  "[vue]": {
+    "editor.defaultFormatter": "biomejs.biome"
+  },
+  "[yaml]": {
+    "editor.defaultFormatter": "biomejs.biome"
   }
 }

.vscode/settings.json

@@ -8,7 +8,7 @@ This project uses **Ultracite**, a zero-config preset that enforces strict code
 - **Check for issues**: `bun x ultracite check`
 - **Diagnose setup**: `bun x ultracite doctor`
 
-ESLint + Prettier + Stylelint (the underlying engine) provides robust linting and formatting. Most issues are automatically fixable.
+Biome (the underlying engine) provides robust linting and formatting. Most issues are automatically fixable.
 
 ---
 
@@ -88,144 +88,14 @@ Write code that is **accessible, performant, type-safe, and maintainable**. Focu
 ### Framework-Specific Guidance
 
 **Next.js:**
-
 - Use Next.js `<Image>` component for images
 - Use `next/head` or App Router metadata API for head elements
 - Use Server Components for async data fetching instead of async Client Components
 
 **React 19+:**
-
 - Use ref as a prop instead of `React.forwardRef`
 
 **Solid/Svelte/Vue/Qwik:**
-
-- Use `class` and `for` attributes (not `className` or `htmlFor`)
-
----
-
-## Testing
-
-- Write assertions inside `it()` or `test()` blocks
-- Avoid done callbacks in async tests - use async/await instead
-- Don't use `.only` or `.skip` in committed code
-- Keep test suites reasonably flat - avoid excessive `describe` nesting
-
-## When ESLint + Prettier + Stylelint Can't Help
-
-ESLint + Prettier + Stylelint's linter will catch most issues automatically. Focus your attention on:
-
-1. **Business logic correctness** - ESLint + Prettier + Stylelint can't validate your algorithms
-2. **Meaningful naming** - Use descriptive names for functions, variables, and types
-3. **Architecture decisions** - Component structure, data flow, and API design
-4. **Edge cases** - Handle boundary conditions and error states
-5. **User experience** - Accessibility, performance, and usability considerations
-6. **Documentation** - Add comments for complex logic, but prefer self-documenting code
-
----
-
-Most formatting and common issues are automatically fixed by ESLint + Prettier + Stylelint. Run `bun x ultracite fix` before committing to ensure compliance.
-
-# Ultracite Code Standards
-
-This project uses **Ultracite**, a zero-config preset that enforces strict code quality standards through automated formatting and linting.
-
-## Quick Reference
-
-- **Format code**: `bun x ultracite fix`
-- **Check for issues**: `bun x ultracite check`
-- **Diagnose setup**: `bun x ultracite doctor`
-
-ESLint + Prettier + Stylelint (the underlying engine) provides robust linting and formatting. Most issues are automatically fixable.
-
----
-
-## Core Principles
-
-Write code that is **accessible, performant, type-safe, and maintainable**. Focus on clarity and explicit intent over brevity.
-
-### Type Safety & Explicitness
-
-- Use explicit types for function parameters and return values when they enhance clarity
-- Prefer `unknown` over `any` when the type is genuinely unknown
-- Use const assertions (`as const`) for immutable values and literal types
-- Leverage TypeScript's type narrowing instead of type assertions
-- Use meaningful variable names instead of magic numbers - extract constants with descriptive names
-
-### Modern JavaScript/TypeScript
-
-- Use arrow functions for callbacks and short functions
-- Prefer `for...of` loops over `.forEach()` and indexed `for` loops
-- Use optional chaining (`?.`) and nullish coalescing (`??`) for safer property access
-- Prefer template literals over string concatenation
-- Use destructuring for object and array assignments
-- Use `const` by default, `let` only when reassignment is needed, never `var`
-
-### Async & Promises
-
-- Always `await` promises in async functions - don't forget to use the return value
-- Use `async/await` syntax instead of promise chains for better readability
-- Handle errors appropriately in async code with try-catch blocks
-- Don't use async functions as Promise executors
-
-### React & JSX
-
-- Use function components over class components
-- Call hooks at the top level only, never conditionally
-- Specify all dependencies in hook dependency arrays correctly
-- Use the `key` prop for elements in iterables (prefer unique IDs over array indices)
-- Nest children between opening and closing tags instead of passing as props
-- Don't define components inside other components
-- Use semantic HTML and ARIA attributes for accessibility:
-  - Provide meaningful alt text for images
-  - Use proper heading hierarchy
-  - Add labels for form inputs
-  - Include keyboard event handlers alongside mouse events
-  - Use semantic elements (`<button>`, `<nav>`, etc.) instead of divs with roles
-
-### Error Handling & Debugging
-
-- Remove `console.log`, `debugger`, and `alert` statements from production code
-- Throw `Error` objects with descriptive messages, not strings or other values
-- Use `try-catch` blocks meaningfully - don't catch errors just to rethrow them
-- Prefer early returns over nested conditionals for error cases
-
-### Code Organization
-
-- Keep functions focused and under reasonable cognitive complexity limits
-- Extract complex conditions into well-named boolean variables
-- Use early returns to reduce nesting
-- Prefer simple conditionals over nested ternary operators
-- Group related code together and separate concerns
-
-### Security
-
-- Add `rel="noopener"` when using `target="_blank"` on links
-- Avoid `dangerouslySetInnerHTML` unless absolutely necessary
-- Don't use `eval()` or assign directly to `document.cookie`
-- Validate and sanitize user input
-
-### Performance
-
-- Avoid spread syntax in accumulators within loops
-- Use top-level regex literals instead of creating them in loops
-- Prefer specific imports over namespace imports
-- Avoid barrel files (index files that re-export everything)
-- Use proper image components (e.g., Next.js `<Image>`) over `<img>` tags
-
-### Framework-Specific Guidance
-
-**Next.js:**
-
-- Use Next.js `<Image>` component for images
-- Use `next/head` or App Router metadata API for head elements
-- Use Server Components for async data fetching instead of async Client Components
-
-**React 19+:**
-
-- Use ref as a prop instead of `React.forwardRef`
-
-**Solid/Svelte/Vue/Qwik:**
-
 - Use `class` and `for` attributes (not `className` or `htmlFor`)
 
 ---
@@ -237,11 +107,11 @@ Write code that is **accessible, performant, type-safe, and maintainable**. Focu
 - Don't use `.only` or `.skip` in committed code
 - Keep test suites reasonably flat - avoid excessive `describe` nesting
 
-## When ESLint + Prettier + Stylelint Can't Help
+## When Biome Can't Help
 
-ESLint + Prettier + Stylelint's linter will catch most issues automatically. Focus your attention on:
+Biome's linter will catch most issues automatically. Focus your attention on:
 
-1. **Business logic correctness** - ESLint + Prettier + Stylelint can't validate your algorithms
+1. **Business logic correctness** - Biome can't validate your algorithms
 2. **Meaningful naming** - Use descriptive names for functions, variables, and types
 3. **Architecture decisions** - Component structure, data flow, and API design
 4. **Edge cases** - Handle boundary conditions and error states
@@ -250,4 +120,4 @@ ESLint + Prettier + Stylelint's linter will catch most issues automatically. Foc
 
 ---
 
-Most formatting and common issues are automatically fixed by ESLint + Prettier + Stylelint. Run `bun x ultracite fix` before committing to ensure compliance.
+Most formatting and common issues are automatically fixed by Biome. Run `bun x ultracite fix` before committing to ensure compliance.

AGENTS.md

@@ -0,0 +1,17 @@
+{
+  "$schema": "./node_modules/@biomejs/biome/configuration_schema.json",
+  "extends": ["ultracite/biome/core", "ultracite/biome/svelte"],
+  "linter": {
+    "rules": {
+      "style": {
+        "useFilenamingConvention": "off"
+      },
+      "suspicious": {
+        "noAssignInExpressions": "info"
+      }
+    }
+  },
+  "files": {
+    "includes": ["**", "!src/env-varlock.d.ts"]
+  }
+}