Enable more biome lints and fix things

packages/coding-agent/src/core/tools/grep.ts

@@ -89,7 +89,7 @@ export const grepTool: AgentTool<typeof grepSchema> = {
 					let searchStat: Stats;
 					try {
 						searchStat = statSync(searchPath);
-					} catch (err) {
+					} catch (_err) {
 						settle(() => reject(new Error(`Path not found: ${searchPath}`)));
 						return;
 					}

packages/coding-agent/src/core/tools/read.ts

@@ -126,7 +126,6 @@ export const readTool: AgentTool<typeof readSchema> = {
 								details = { truncation };
 							} else if (userLimitedLines !== undefined && startLine + userLimitedLines < allLines.length) {
 								// User specified limit, there's more content, but no truncation
-								const endLineDisplay = startLineDisplay + userLimitedLines - 1;
 								const remaining = allLines.length - (startLine + userLimitedLines);
 								const nextOffset = startLine + userLimitedLines + 1;
 

packages/coding-agent/src/core/tools/truncate.ts

@@ -261,5 +261,5 @@ export function truncateLine(
 	if (line.length <= maxChars) {
 		return { text: line, wasTruncated: false };
 	}
-	return { text: line.slice(0, maxChars) + "... [truncated]", wasTruncated: true };
+	return { text: `${line.slice(0, maxChars)}... [truncated]`, wasTruncated: true };
 }