diag: switch to print() for visibility, add elapsed timing

fix: remove unused Browser import, let browser_use manage browser internally

diag: add detailed logging around agent.run() result

fix: use gemini-2.5-flash-lite (no rate limits) as primary (browser_agent.py)

fix: explicit Browser+no-sandbox, switch to llama-3.3-70b free model

fix: extract final_result() from AgentHistoryList, add max_steps=25

fix: switch to gemini-2.5-flash-lite, expand retry pattern (browser_agent.py)

fix: add exception logging to surface real LLM error

fix: update model IDs to current OpenRouter free models (browser_agent.py)

feat: initial KAZE browser-use HF Space