Add gaming deals Matrix bot

Implements a Matrix bot that posts PC gaming deals and free game alerts:
- CheapShark API integration (Steam, GOG, Humble, GMG) polled every 2 hours
- Epic Games Store free games detection polled daily
- IsThereAnyDeal historical low price flagging (optional)
- SQLite deduplication with 30-day pruning
- First-run population (records existing deals without posting)
- Matrix-flavored HTML + plain text fallback messages
- Dockerfile for containerized deployment

https://claude.ai/code/session_01LPpSZFfyh6vdV5HGFWjoQX

gaming_deals_bot/formatter.py

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+"""Message formatting for Matrix deal posts.
+
+Produces both a plain-text fallback and HTML formatted body for Matrix messages.
+"""
+
+from datetime import datetime, timezone
+
+import markdown
+
+from .cheapshark import CheapSharkDeal
+from .epic import EpicFreeGame
+
+_md = markdown.Markdown()
+
+
+def _render_html(md_text: str) -> str:
+    """Convert Markdown to HTML, resetting the parser between calls."""
+    _md.reset()
+    return _md.convert(md_text)
+
+
+def format_deal(deal: CheapSharkDeal, is_historical_low: bool = False) -> tuple[str, str]:
+    """Format a CheapShark deal into (plain_text, html) for Matrix.
+
+    Returns (body, formatted_body).
+    """
+    discount = int(deal.savings)
+    lines = [
+        f"**🎮 [DEAL] {deal.title}**",
+        f"> {discount}% off — **${deal.sale_price}** on {deal.store_name} ~~${deal.normal_price}~~",
+    ]
+
+    if is_historical_low:
+        lines.append("> 🏆 _All-time low!_")
+
+    lines.append(f"> 🔗 [View Deal]({deal.deal_url})")
+
+    md_text = "\n".join(lines)
+    html = _render_html(md_text)
+
+    # Plain text fallback — strip markdown syntax
+    plain_lines = [
+        f"🎮 [DEAL] {deal.title}",
+        f"  {discount}% off — ${deal.sale_price} on {deal.store_name} (was ${deal.normal_price})",
+    ]
+    if is_historical_low:
+        plain_lines.append("  🏆 All-time low!")
+    plain_lines.append(f"  🔗 {deal.deal_url}")
+
+    plain_text = "\n".join(plain_lines)
+
+    return plain_text, html
+
+
+def format_epic_free(game: EpicFreeGame) -> tuple[str, str]:
+    """Format an Epic free game into (plain_text, html) for Matrix.
+
+    Returns (body, formatted_body).
+    """
+    lines = [
+        f"**🆓 [FREE] {game.title}**",
+        "> Free on Epic Games Store",
+    ]
+
+    if game.end_date:
+        try:
+            end_dt = datetime.fromisoformat(game.end_date.replace("Z", "+00:00"))
+            date_str = end_dt.strftime("%B %-d")
+            lines.append(f"> 📅 _Free until {date_str}_")
+        except (ValueError, TypeError):
+            pass
+
+    if game.url:
+        lines.append(f"> 🔗 [Claim Now]({game.url})")
+
+    md_text = "\n".join(lines)
+    html = _render_html(md_text)
+
+    # Plain text fallback
+    plain_lines = [
+        f"🆓 [FREE] {game.title}",
+        "  Free on Epic Games Store",
+    ]
+    if game.end_date:
+        try:
+            end_dt = datetime.fromisoformat(game.end_date.replace("Z", "+00:00"))
+            date_str = end_dt.strftime("%B %-d")
+            plain_lines.append(f"  📅 Free until {date_str}")
+        except (ValueError, TypeError):
+            pass
+    if game.url:
+        plain_lines.append(f"  🔗 {game.url}")
+
+    plain_text = "\n".join(plain_lines)
+
+    return plain_text, html
+
+
+def format_epic_upcoming(game: EpicFreeGame) -> tuple[str, str]:
+    """Format an upcoming Epic free game into (plain_text, html) for Matrix."""
+    lines = [
+        f"**📢 [UPCOMING FREE] {game.title}**",
+        "> Coming soon — Free on Epic Games Store",
+    ]
+
+    if game.end_date:
+        try:
+            end_dt = datetime.fromisoformat(game.end_date.replace("Z", "+00:00"))
+            date_str = end_dt.strftime("%B %-d")
+            lines.append(f"> 📅 _Free until {date_str}_")
+        except (ValueError, TypeError):
+            pass
+
+    if game.url:
+        lines.append(f"> 🔗 [Store Page]({game.url})")
+
+    md_text = "\n".join(lines)
+    html = _render_html(md_text)
+
+    plain_lines = [
+        f"📢 [UPCOMING FREE] {game.title}",
+        "  Coming soon — Free on Epic Games Store",
+    ]
+    if game.url:
+        plain_lines.append(f"  🔗 {game.url}")
+
+    plain_text = "\n".join(plain_lines)
+
+    return plain_text, html