Add Reddit monitoring bot — backend, frontend, and Docker config

Python/FastAPI backend with PostgreSQL for collecting Reddit data via
public .json endpoints. React/Vite dashboard for analytics. Docker Compose
setup with API and worker services connecting to shared PostgreSQL.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

backend/schemas/subreddit.py

@@ -0,0 +1,24 @@
+from datetime import datetime
+from pydantic import BaseModel
+
+
+class SubredditCreate(BaseModel):
+    name: str
+
+
+class SubredditUpdate(BaseModel):
+    is_active: bool | None = None
+
+
+class SubredditResponse(BaseModel):
+    id: int
+    name: str
+    display_name: str | None
+    description: str | None
+    subscribers: int | None
+    is_active: bool
+    created_at: datetime
+    updated_at: datetime
+    post_count: int = 0
+
+    model_config = {"from_attributes": True}