chore(web): migrate from ESLint+Prettier to Biome

- Install @biomejs/[email protected] as unified linter and formatter
- Remove ESLint, Prettier and all related plugins (221 packages removed)
- Migrate linting rules from ESLint to Biome configuration
- Migrate formatting rules from Prettier to Biome configuration
- Exclude auto-generated proto files from linting (src/types/proto/**)
- Exclude CSS files from Biome (Tailwind syntax not yet supported)
- Update package.json scripts:
  - lint: tsc + biome check
  - lint:fix: biome check --write
  - format: biome format --write
- Auto-fix import organization across 60+ files
- Fix duplicate key in Russian locale (ru.json)
- Update CLAUDE.md documentation to reflect Biome usage

Benefits:
- 10-100x faster linting performance
- Simplified toolchain with single configuration file
- 221 fewer npm dependencies
- Unified linting, formatting, and import organization

Author: boojack

CLAUDE.md

@@ -60,10 +60,12 @@ pnpm build                       # Build to web/dist/
 pnpm release                     # Build and copy to server/router/frontend/dist/
 ```
 
-**Lint:**
+**Lint and Format:**
 ```bash
 cd web
-pnpm lint                        # TypeScript check + ESLint
+pnpm lint                        # TypeScript check + Biome lint
+pnpm lint:fix                    # Auto-fix linting issues
+pnpm format                      # Format code with Biome
 ```
 
 ### CLI Flags and Environment Variables
@@ -209,9 +211,10 @@ The frontend uses `nice-grpc-web` to call backend services. Client setup is in `
 
 - **Components:** PascalCase filenames (e.g., `MemoEditor.tsx`)
 - **Hooks:** camelCase filenames (e.g., `useMemoList.ts`)
-- **Formatting:** Prettier enforced (see `web/.prettierrc.js`)
-- **Import Ordering:** Managed by `@trivago/prettier-plugin-sort-imports`
+- **Formatting:** Biome enforced (see `web/biome.json`)
+- **Import Ordering:** Automatic via Biome's organize imports
 - **Styling:** Tailwind utility classes preferred over custom CSS
+- **Linting:** Biome replaces ESLint and Prettier for faster, unified tooling
 
 ### Commit Messages
 
@@ -338,6 +341,7 @@ For SQLite (default), all data is stored in the directory specified by `--data`
 - `react-router-dom` - Routing
 - `mobx` / `mobx-react-lite` - State management
 - `tailwindcss` - Styling
+- `@biomejs/biome` - Fast linter and formatter (replaces ESLint + Prettier)
 - `nice-grpc-web` - gRPC-Web client
 - `@radix-ui/*` - Headless UI components
 - `react-i18next` - Internationalization

web/.prettierrc.js

@@ -0,0 +1,202 @@
+{
+	"$schema": "https://biomejs.dev/schemas/2.3.5/schema.json",
+	"vcs": {
+		"enabled": true,
+		"clientKind": "git",
+		"useIgnoreFile": true
+	},
+	"files": {
+		"includes": [
+			"**",
+			"!!**/dist",
+			"!src/types/proto"
+		],
+		"ignoreUnknown": true
+	},
+	"formatter": {
+		"enabled": true,
+		"formatWithErrors": false,
+		"indentStyle": "space",
+		"indentWidth": 2,
+		"lineEnding": "lf",
+		"lineWidth": 140,
+		"attributePosition": "auto",
+		"bracketSameLine": false,
+		"bracketSpacing": true,
+		"expand": "auto",
+		"useEditorconfig": true
+	},
+	"linter": {
+		"enabled": true,
+		"rules": {
+			"recommended": false,
+			"complexity": {
+				"noAdjacentSpacesInRegex": "error",
+				"noExtraBooleanCast": "error",
+				"noUselessCatch": "error",
+				"noUselessEscapeInRegex": "error",
+				"noUselessTypeConstraint": "error"
+			},
+			"correctness": {
+				"noConstAssign": "error",
+				"noConstantCondition": "error",
+				"noEmptyCharacterClassInRegex": "error",
+				"noEmptyPattern": "error",
+				"noGlobalObjectCalls": "error",
+				"noInvalidBuiltinInstantiation": "error",
+				"noInvalidConstructorSuper": "error",
+				"noNonoctalDecimalEscape": "error",
+				"noPrecisionLoss": "error",
+				"noSelfAssign": "error",
+				"noSetterReturn": "error",
+				"noSwitchDeclarations": "error",
+				"noUndeclaredVariables": "error",
+				"noUnreachable": "error",
+				"noUnreachableSuper": "error",
+				"noUnsafeFinally": "error",
+				"noUnsafeOptionalChaining": "error",
+				"noUnusedLabels": "error",
+				"noUnusedPrivateClassMembers": "error",
+				"noUnusedVariables": "error",
+				"useIsNan": "error",
+				"useValidForDirection": "error",
+				"useValidTypeof": "error",
+				"useYield": "error"
+			},
+			"style": {
+				"noCommonJs": "error",
+				"noNamespace": "error",
+				"useArrayLiterals": "error",
+				"useAsConstAssertion": "error",
+				"useBlockStatements": "off"
+			},
+			"suspicious": {
+				"noAsyncPromiseExecutor": "error",
+				"noCatchAssign": "error",
+				"noClassAssign": "error",
+				"noCompareNegZero": "error",
+				"noConstantBinaryExpressions": "error",
+				"noControlCharactersInRegex": "error",
+				"noDebugger": "error",
+				"noDuplicateCase": "error",
+				"noDuplicateClassMembers": "error",
+				"noDuplicateElseIf": "error",
+				"noDuplicateObjectKeys": "error",
+				"noDuplicateParameters": "error",
+				"noEmptyBlockStatements": "off",
+				"noExplicitAny": "off",
+				"noExtraNonNullAssertion": "error",
+				"noFallthroughSwitchClause": "error",
+				"noFunctionAssign": "error",
+				"noGlobalAssign": "error",
+				"noImportAssign": "error",
+				"noIrregularWhitespace": "error",
+				"noMisleadingCharacterClass": "error",
+				"noMisleadingInstantiator": "error",
+				"noNonNullAssertedOptionalChain": "error",
+				"noPrototypeBuiltins": "error",
+				"noRedeclare": "error",
+				"noShadowRestrictedNames": "error",
+				"noSparseArray": "error",
+				"noUnsafeDeclarationMerging": "error",
+				"noUnsafeNegation": "error",
+				"noUselessRegexBackrefs": "error",
+				"noWith": "error",
+				"useGetterReturn": "error",
+				"useNamespaceKeyword": "error"
+			}
+		},
+		"includes": [
+			"**",
+			"!**/dist/**",
+			"!**/node_modules/**",
+			"!src/types/proto/**"
+		]
+	},
+	"javascript": {
+		"formatter": {
+			"jsxQuoteStyle": "double",
+			"quoteProperties": "asNeeded",
+			"trailingCommas": "all",
+			"semicolons": "always",
+			"arrowParentheses": "always",
+			"bracketSameLine": false,
+			"quoteStyle": "double",
+			"attributePosition": "auto",
+			"bracketSpacing": true
+		},
+		"globals": []
+	},
+	"css": {
+		"parser": {
+			"cssModules": false,
+			"allowWrongLineComments": true,
+			"tailwindDirectives": true
+		}
+	},
+	"html": {
+		"formatter": {
+			"indentScriptAndStyle": false,
+			"selfCloseVoidElements": "always"
+		}
+	},
+	"overrides": [
+		{
+			"includes": [
+				"**/*.ts",
+				"**/*.tsx",
+				"**/*.mts",
+				"**/*.cts"
+			],
+			"linter": {
+				"rules": {
+					"complexity": {
+						"noArguments": "error"
+					},
+					"correctness": {
+						"noConstAssign": "off",
+						"noGlobalObjectCalls": "off",
+						"noInvalidBuiltinInstantiation": "off",
+						"noInvalidConstructorSuper": "off",
+						"noSetterReturn": "off",
+						"noUndeclaredVariables": "off",
+						"noUnreachable": "off",
+						"noUnreachableSuper": "off"
+					},
+					"style": {
+						"useConst": "error"
+					},
+					"suspicious": {
+						"noClassAssign": "off",
+						"noDuplicateClassMembers": "off",
+						"noDuplicateObjectKeys": "off",
+						"noDuplicateParameters": "off",
+						"noFunctionAssign": "off",
+						"noImportAssign": "off",
+						"noRedeclare": "off",
+						"noUnsafeNegation": "off",
+						"noVar": "error",
+						"noWith": "off",
+						"useGetterReturn": "off"
+					}
+				}
+			}
+		},
+		{
+			"includes": [
+				"src/utils/i18n.ts"
+			],
+			"linter": {
+				"rules": {}
+			}
+		}
+	],
+	"assist": {
+		"enabled": true,
+		"actions": {
+			"source": {
+				"organizeImports": "on"
+			}
+		}
+	}
+}

web/biome.json

@@ -5,7 +5,9 @@
     "dev": "vite",
     "build": "vite build",
     "release": "vite build --mode release --outDir=../server/router/frontend/dist --emptyOutDir",
-    "lint": "tsc --noEmit --skipLibCheck && eslint --ext .js,.ts,.tsx, src"
+    "lint": "tsc --noEmit --skipLibCheck && biome check src",
+    "lint:fix": "biome check --write src",
+    "format": "biome format --write src"
   },
   "dependencies": {
     "@dnd-kit/core": "^6.3.1",
@@ -63,9 +65,8 @@
     "uuid": "^11.1.0"
   },
   "devDependencies": {
+    "@biomejs/biome": "2.3.5",
     "@bufbuild/protobuf": "^2.8.0",
-    "@eslint/js": "^9.35.0",
-    "@trivago/prettier-plugin-sort-imports": "^5.2.2",
     "@types/d3": "^7.4.3",
     "@types/katex": "^0.16.7",
     "@types/leaflet": "^1.9.20",
@@ -79,17 +80,11 @@
     "@types/unist": "^3.0.3",
     "@types/uuid": "^10.0.0",
     "@vitejs/plugin-react": "^4.7.0",
-    "eslint": "^9.35.0",
-    "eslint-config-prettier": "^10.1.8",
-    "eslint-plugin-prettier": "^5.5.4",
-    "eslint-plugin-react": "^7.37.5",
     "long": "^5.3.2",
     "nice-grpc-web": "^3.3.8",
-    "prettier": "^3.6.2",
     "terser": "^5.44.0",
     "tw-animate-css": "^1.4.0",
     "typescript": "^5.9.3",
-    "typescript-eslint": "^8.45.0",
     "vite": "^7.1.5"
   },
   "pnpm": {