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/routers/posts.py

@@ -0,0 +1,64 @@
+from datetime import datetime
+from fastapi import APIRouter, Depends, HTTPException, Query
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from backend.database import get_db
+from backend.schemas.post import PostResponse, PostDetailResponse
+from backend.services import post_service
+from backend.models.metric_snapshot import MetricSnapshot
+from sqlalchemy import select
+
+router = APIRouter(prefix="/posts", tags=["posts"])
+
+
+@router.get("")
+async def list_posts(
+    subreddit_id: int | None = None,
+    author: str | None = None,
+    flair: str | None = None,
+    sort_by: str = Query("created_utc", pattern="^(created_utc|score|num_comments)$"),
+    sort_order: str = Query("desc", pattern="^(asc|desc)$"),
+    since: datetime | None = None,
+    until: datetime | None = None,
+    page: int = Query(1, ge=1),
+    per_page: int = Query(25, ge=1, le=100),
+    db: AsyncSession = Depends(get_db),
+):
+    posts, total = await post_service.list_posts(
+        db, subreddit_id, author, flair, sort_by, sort_order, since, until, page, per_page
+    )
+    return {
+        "data": posts,
+        "total": total,
+        "page": page,
+        "per_page": per_page,
+        "pages": (total + per_page - 1) // per_page if per_page else 0,
+    }
+
+
+@router.get("/{post_id}")
+async def get_post(post_id: int, db: AsyncSession = Depends(get_db)):
+    post = await post_service.get_post(db, post_id)
+    if not post:
+        raise HTTPException(status_code=404, detail="Post not found")
+    return post
+
+
+@router.get("/{post_id}/snapshots")
+async def get_post_snapshots(post_id: int, db: AsyncSession = Depends(get_db)):
+    stmt = (
+        select(MetricSnapshot)
+        .where(MetricSnapshot.post_id == post_id)
+        .order_by(MetricSnapshot.snapshot_at.asc())
+    )
+    result = await db.execute(stmt)
+    snapshots = result.scalars().all()
+    return [
+        {
+            "score": s.score,
+            "num_comments": s.num_comments,
+            "upvote_ratio": s.upvote_ratio,
+            "snapshot_at": s.snapshot_at,
+        }
+        for s in snapshots
+    ]