feat: initialize events app with calendars, slots, tickets, and internal API

Extract events/calendar functionality into standalone microservice:
- app.py and events_api.py from apps/events/
- Calendar blueprints (calendars, calendar, calendar_entries, calendar_entry, day, slots, slot, ticket_types, ticket_type)
- Templates for all calendar/event views including admin
- Dockerfile (APP_MODULE=app:app, IMAGE=events)
- entrypoint.sh (no Alembic - migrations managed by blog app)
- Gitea CI workflow for build and deploy

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

bp/calendar/services/calendar_view.py

@@ -0,0 +1,109 @@
+from __future__ import annotations
+
+from datetime import datetime, timezone
+from typing import Optional
+import calendar as pycalendar
+
+from quart import request
+from sqlalchemy import select
+from sqlalchemy.ext.asyncio import AsyncSession
+from sqlalchemy.orm import selectinload, with_loader_criteria
+
+from models.calendars import Calendar, CalendarSlot
+
+
+def parse_int_arg(name: str, default: Optional[int] = None) -> Optional[int]:
+    """Parse an integer query parameter from the request."""
+    val = request.args.get(name, "").strip()
+    if not val:
+        return default
+    try:
+        return int(val)
+    except ValueError:
+        return default
+
+
+def add_months(year: int, month: int, delta: int) -> tuple[int, int]:
+    """Add (or subtract) months to a given year/month, handling year overflow."""
+    new_month = month + delta
+    new_year = year + (new_month - 1) // 12
+    new_month = ((new_month - 1) % 12) + 1
+    return new_year, new_month
+
+
+def build_calendar_weeks(year: int, month: int) -> list[list[dict]]:
+    """
+    Build a calendar grid for the given year and month.
+    Returns a list of weeks, where each week is a list of 7 day dictionaries.
+    """
+    today = datetime.now(timezone.utc).date()
+    cal = pycalendar.Calendar(firstweekday=0)  # 0 = Monday
+    weeks: list[list[dict]] = []
+
+    for week in cal.monthdatescalendar(year, month):
+        week_days = []
+        for d in week:
+            week_days.append(
+                {
+                    "date": d,
+                    "in_month": (d.month == month),
+                    "is_today": (d == today),
+                }
+            )
+        weeks.append(week_days)
+
+    return weeks
+
+
+async def get_calendar_by_post_and_slug(
+    session: AsyncSession,
+    post_id: int,
+    calendar_slug: str,
+) -> Optional[Calendar]:
+    """
+    Fetch a calendar by post_id and slug, with slots eagerly loaded.
+    Returns None if not found.
+    """
+    result = await session.execute(
+        select(Calendar)
+        .options(
+            selectinload(Calendar.slots),
+            with_loader_criteria(CalendarSlot, CalendarSlot.deleted_at.is_(None)),
+        )
+        .where(
+            Calendar.post_id == post_id,
+            Calendar.slug == calendar_slug,
+            Calendar.deleted_at.is_(None),
+        )
+    )
+    return result.scalar_one_or_none()
+
+
+async def get_calendar_by_slug(
+    session: AsyncSession,
+    calendar_slug: str,
+) -> Optional[Calendar]:
+    """
+    Fetch a calendar by slug only (for standalone events service).
+    With slots eagerly loaded. Returns None if not found.
+    """
+    result = await session.execute(
+        select(Calendar)
+        .options(
+            selectinload(Calendar.slots),
+            with_loader_criteria(CalendarSlot, CalendarSlot.deleted_at.is_(None)),
+        )
+        .where(
+            Calendar.slug == calendar_slug,
+            Calendar.deleted_at.is_(None),
+        )
+    )
+    return result.scalar_one_or_none()
+
+
+async def update_calendar_description(
+    calendar: Calendar,
+    description: Optional[str],
+) -> None:
+    """Update calendar description (in-place on the calendar object)."""
+    calendar.description = description or None