v4.3: pre-filter layer — zero API cost spam defense

fix: pass BLOCK_NONE safety_settings on every API call, not just constructor

fix: safe Gemini response extraction + startup logging

v3.0: international edition — universal prompts, English UI, multilingual bot

fix: relax Gemini safety filters — BLOCK_NONE for all categories

v1.0: TelegramGuard - AI-powered group guardian with I-Lang Prompt Spec