style(deps): migrated from Prettier to Biome and updated formatting rules

- Removed Prettier configuration files (.prettierignore and .prettierrc) and migrated formatting to Biome.
- Updated Biome configuration from version 2.3.11 to 2.3.12 and changed arrowParentheses rule from 'always' to 'asNeeded'.
- Pinned @biomejs/biome dependency to exact version 2.3.12 in package.json and bun.lock.
- Applied consistent arrow function formatting across 489 files by removing unnecessary parentheses around single parameters.
- Removed blank lines after comment blocks and reorganized imports for consistency across the codebase.

packages/coding-agent/test/tools/python-fallback.test.ts

@@ -41,7 +41,7 @@ describe("createTools python fallback", () => {
 		});
 
 		const tools = await createTools(session, ["python"]);
-		const names = tools.map((tool) => tool.name).sort();
+		const names = tools.map(tool => tool.name).sort();
 
 		expect(names).toEqual(["bash"]);
 
@@ -61,7 +61,7 @@ describe("createTools python fallback", () => {
 		});
 
 		const tools = await createTools(session);
-		const names = tools.map((tool) => tool.name);
+		const names = tools.map(tool => tool.name);
 
 		expect(names).toContain("bash");
 		expect(names).not.toContain("python");