Add multi-user features: i18n, payments, multi-model AI, focus areas

Replace single report type with composable analysis: depth levels
(basic/standard/full) + focus area multi-select (psychology, business,
marketing, content, audience, sentiment). Multi-step inline keyboard
flow guides users through selection.

- i18n: English + Russian, auto-detect from Telegram, /lang override
- AI providers: Anthropic + OpenRouter via AIClient abstraction
- Telegram Stars payments with per-depth pricing and free trial
- SQLite (aiosqlite) for users, analyses, payments tracking
- User middleware for auto-registration and language detection
- Report persistence: save .md locally, offer file download
- New commands: /features, /prices, /lang
- Composable prompt system: depth modifiers + focus area fragments

bot/config.py

@@ -9,7 +9,22 @@ class Settings(BaseSettings):
     anthropic_api_key: str
     claude_model: str = "claude-opus-4-6"
 
+    openrouter_api_key: str = ""
+    available_models: str = "claude-haiku-4-5"
+
+    price_basic: int = 50
+    price_standard: int = 100
+    price_full: int = 200
+    free_analyses: int = 1
+
+    db_path: str = "/app/data/bot.db"
+    reports_dir: str = "/app/data/reports"
+
     model_config = {"env_file": ".env", "env_file_encoding": "utf-8", "extra": "ignore"}
 
+    @property
+    def models_list(self) -> list[str]:
+        return [m.strip() for m in self.available_models.split(",") if m.strip()]
+
 
 settings = Settings()