add lint/format scripts and fix all biome errors (#233)

Add `lint`, `lint:fix`, `format`, and `format:fix` package.json scripts
backed by biome. Add AGENTS.md rule for agents to run them after changes.
Fix all existing lint and format violations across the codebase.

Co-authored-by: Cursor <cursoragent@cursor.com>

test/adhoc/pushDisabled.ts

@@ -1,5 +1,5 @@
 import type { AgentResult, TestRunnerOptions, ValidationCheck } from "../utils.ts";
-import { defineFixture, getAgentOutput, getStructuredOutput } from "../utils.ts";
+import { defineFixture, getStructuredOutput } from "../utils.ts";
 
 /**
  * push disabled test - validates that all push operations are blocked.