treewide: migrate from ESLint/Prettier to Biome

- Add Biome for linting and formatting .ts/.js/.css files
- Keep Prettier for Svelte files only (Biome can't parse Svelte templates)
- Enable Tailwind CSS class sorting via useSortedClasses
- Enable noFloatingPromises rule
- Use Prettier-style formatting (2 spaces, trailing commas)
- Update tsconfig: disable noPropertyAccessFromIndexSignature
- Remove ESLint and related dependencies

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: aster-void

.prettierignore

@@ -1,10 +1,3 @@
-# Package Managers
-package-lock.json
-pnpm-lock.yaml
-yarn.lock
-bun.lock
-bun.lockb
-
-# Miscellaneous
-/static/
-/drizzle/
+# Prettier only handles Svelte files (Biome handles the rest)
+*
+!**/*.svelte

.prettierrc

@@ -1,4 +1,6 @@
 printWidth: 100
+useTabs: false
+tabWidth: 2
 plugins:
   - prettier-plugin-svelte
   - prettier-plugin-tailwindcss

biome.json

@@ -0,0 +1,46 @@
+{
+  "$schema": "https://biomejs.dev/schemas/2.3.10/schema.json",
+  "vcs": {
+    "enabled": true,
+    "clientKind": "git",
+    "useIgnoreFile": true
+  },
+  "files": {
+    "ignoreUnknown": true,
+    "includes": ["**", "!**/*.svelte"]
+  },
+  "formatter": {
+    "enabled": true,
+    "indentStyle": "space",
+    "indentWidth": 2,
+    "lineWidth": 100
+  },
+  "linter": {
+    "enabled": true,
+    "rules": {
+      "recommended": true,
+      "nursery": {
+        "noFloatingPromises": "error",
+        "useSortedClasses": {
+          "level": "error",
+          "fix": "safe",
+          "options": {
+            "functions": ["clsx", "cva", "tw"]
+          }
+        }
+      }
+    }
+  },
+  "javascript": {
+    "formatter": {
+      "quoteStyle": "double",
+      "trailingCommas": "all"
+    }
+  },
+  "css": {
+    "parser": {
+      "cssModules": true,
+      "tailwindDirectives": true
+    }
+  }
+}

bun.lock

@@ -111,12 +111,8 @@
           "name": "account_user_id_user_id_fk",
           "tableFrom": "account",
           "tableTo": "user",
-          "columnsFrom": [
-            "user_id"
-          ],
-          "columnsTo": [
-            "id"
-          ],
+          "columnsFrom": ["user_id"],
+          "columnsTo": ["id"],
           "onDelete": "cascade",
           "onUpdate": "no action"
         }
@@ -230,12 +226,8 @@
           "name": "article_author_id_member_id_fk",
           "tableFrom": "article",
           "tableTo": "member",
-          "columnsFrom": [
-            "author_id"
-          ],
-          "columnsTo": [
-            "id"
-          ],
+          "columnsFrom": ["author_id"],
+          "columnsTo": ["id"],
           "onDelete": "set null",
           "onUpdate": "no action"
         }
@@ -245,9 +237,7 @@
         "article_slug_unique": {
           "name": "article_slug_unique",
           "nullsNotDistinct": false,
-          "columns": [
-            "slug"
-          ]
+          "columns": ["slug"]
         }
       },
       "policies": {},
@@ -337,12 +327,8 @@
           "name": "member_user_id_user_id_fk",
           "tableFrom": "member",
           "tableTo": "user",
-          "columnsFrom": [
-            "user_id"
-          ],
-          "columnsTo": [
-            "id"
-          ],
+          "columnsFrom": ["user_id"],
+          "columnsTo": ["id"],
           "onDelete": "set null",
           "onUpdate": "no action"
         }
@@ -352,16 +338,12 @@
         "member_user_id_unique": {
           "name": "member_user_id_unique",
           "nullsNotDistinct": false,
-          "columns": [
-            "user_id"
-          ]
+          "columns": ["user_id"]
         },
         "member_slug_unique": {
           "name": "member_slug_unique",
           "nullsNotDistinct": false,
-          "columns": [
-            "slug"
-          ]
+          "columns": ["slug"]
         }
       },
       "policies": {},
@@ -449,9 +431,7 @@
         "project_slug_unique": {
           "name": "project_slug_unique",
           "nullsNotDistinct": false,
-          "columns": [
-            "slug"
-          ]
+          "columns": ["slug"]
         }
       },
       "policies": {},
@@ -510,25 +490,17 @@
           "name": "project_member_project_id_project_id_fk",
           "tableFrom": "project_member",
           "tableTo": "project",
-          "columnsFrom": [
-            "project_id"
-          ],
-          "columnsTo": [
-            "id"
-          ],
+          "columnsFrom": ["project_id"],
+          "columnsTo": ["id"],
           "onDelete": "cascade",
           "onUpdate": "no action"
         },
         "project_member_member_id_member_id_fk": {
           "name": "project_member_member_id_member_id_fk",
           "tableFrom": "project_member",
           "tableTo": "member",
-          "columnsFrom": [
-            "member_id"
-          ],
-          "columnsTo": [
-            "id"
-          ],
+          "columnsFrom": ["member_id"],
+          "columnsTo": ["id"],
           "onDelete": "cascade",
           "onUpdate": "no action"
         }
@@ -616,12 +588,8 @@
           "name": "session_user_id_user_id_fk",
           "tableFrom": "session",
           "tableTo": "user",
-          "columnsFrom": [
-            "user_id"
-          ],
-          "columnsTo": [
-            "id"
-          ],
+          "columnsFrom": ["user_id"],
+          "columnsTo": ["id"],
           "onDelete": "cascade",
           "onUpdate": "no action"
         }
@@ -631,9 +599,7 @@
         "session_token_unique": {
           "name": "session_token_unique",
           "nullsNotDistinct": false,
-          "columns": [
-            "token"
-          ]
+          "columns": ["token"]
         }
       },
       "policies": {},
@@ -703,9 +669,7 @@
         "user_email_unique": {
           "name": "user_email_unique",
           "nullsNotDistinct": false,
-          "columns": [
-            "email"
-          ]
+          "columns": ["email"]
         }
       },
       "policies": {},
@@ -791,4 +755,4 @@
     "schemas": {},
     "tables": {}
   }
-}
+}

drizzle/meta/0000_snapshot.json

@@ -10,4 +10,4 @@
       "breakpoints": true
     }
   ]
-}
+}

drizzle/meta/_journal.json

@@ -11,15 +11,15 @@
     "prepare": "svelte-kit sync",
     "test-check": "bun test",
     "check": "bun type-check && bun test-check && bun lint-check && bun format-check",
-    "fix": "bun lint-fix && bun format",
-    "tidy": "bun type-check && bun test-check && bun --bun lint-fix --quiet && bun --bun format --log-level silent",
+    "fix": "biome check --fix && prettier --write .",
+    "tidy": "bun type-check && bun test-check && biome check --fix && prettier --write .",
     "type-check": "svelte-kit sync && svelte-check --tsconfig ./tsconfig.json",
     "check:watch": "svelte-kit sync && svelte-check --tsconfig ./tsconfig.json --watch",
-    "format": "prettier --write .",
-    "format-check": "prettier --check .",
-    "lint-check": "eslint .",
+    "format": "biome format --write . && prettier --write .",
+    "format-check": "biome format . && prettier --check .",
+    "lint-check": "biome lint .",
     "lint": "bun lint-check",
-    "lint-fix": "eslint . --fix",
+    "lint-fix": "biome lint --fix .",
     "db": "drizzle-kit",
     "up": "bun db push --force && devenv processes up -d",
     "down": "devenv processes down",
@@ -28,8 +28,7 @@
     "logs": "tail -f ./.devenv/processes.log"
   },
   "devDependencies": {
-    "@eslint/compat": "^1.4.0",
-    "@eslint/js": "^9.39.1",
+    "@biomejs/biome": "^2.3.10",
     "@sveltejs/adapter-node": "^5.4.0",
     "@sveltejs/kit": "^2.49.1",
     "@sveltejs/vite-plugin-svelte": "^6.2.1",
@@ -40,19 +39,14 @@
     "daisyui": "^5.5.13",
     "drizzle-kit": "^0.31.8",
     "drizzle-orm": "^0.45.0",
-    "eslint": "^9.39.1",
-    "eslint-config-prettier": "^10.1.8",
-    "eslint-plugin-svelte": "^3.13.1",
-    "globals": "^16.5.0",
     "postgres": "^3.4.5",
     "prettier": "^3.7.4",
-    "prettier-plugin-svelte": "^3.4.0",
+    "prettier-plugin-svelte": "^3.4.1",
     "prettier-plugin-tailwindcss": "^0.7.2",
     "svelte": "^5.45.6",
     "svelte-check": "^4.3.4",
     "tailwindcss": "^4.1.17",
     "typescript": "^5.9.3",
-    "typescript-eslint": "^8.48.1",
     "vite": "^7.2.6",
     "yaml": "^2.8.2"
   },

eslint.config.js

@@ -13,12 +13,12 @@
  */
 
 import { readdir, readFile } from "node:fs/promises";
-import { join, dirname } from "node:path";
-import { parse as parseYaml } from "yaml";
-import { drizzle } from "drizzle-orm/libsql";
+import { dirname, join } from "node:path";
 import { createClient } from "@libsql/client";
-import { article, member } from "../src/lib/shared/models/schema";
 import { eq } from "drizzle-orm";
+import { drizzle } from "drizzle-orm/libsql";
+import { parse as parseYaml } from "yaml";
+import { article, member } from "../src/lib/shared/models/schema";
 
 // Create database client directly (not using SvelteKit path aliases)
 const DATABASE_URL = process.env.DATABASE_URL;
@@ -104,7 +104,7 @@ function generateExcerpt(content: string, maxLength = 200): string {
     .trim();
 
   if (plain.length <= maxLength) return plain;
-  return plain.slice(0, maxLength).replace(/\s+\S*$/, "") + "...";
+  return `${plain.slice(0, maxLength).replace(/\s+\S*$/, "")}...`;
 }
 
 async function findArticleFiles(): Promise<string[]> {
@@ -196,14 +196,14 @@ function extractErrorMessage(error: unknown): string {
 
   // Truncate very long messages
   if (message.length > 200) {
-    return message.slice(0, 200) + "...";
+    return `${message.slice(0, 200)}...`;
   }
 
   return message;
 }
 
 async function migrateArticle(filePath: string, dryRun: boolean): Promise<MigrationResult> {
-  const relPath = filePath.replace(ARTICLES_PATH + "/", "");
+  const relPath = filePath.replace(`${ARTICLES_PATH}/`, "");
   const dirPath = dirname(relPath);
   const slug = generateSlug(dirPath);