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/calendars/routes.py

@@ -0,0 +1,98 @@
+from __future__ import annotations
+
+from quart import (
+    request, render_template, make_response, Blueprint, g
+)
+from sqlalchemy import select
+
+from models.calendars import Calendar
+
+from .services.calendars import (
+    create_calendar as svc_create_calendar,
+)
+
+from ..calendar.routes import register as register_calendar
+
+from suma_browser.app.redis_cacher import cache_page, clear_cache
+
+from suma_browser.app.authz import require_admin
+from suma_browser.app.utils.htmx import is_htmx_request
+
+
+def register():
+    bp = Blueprint("calendars", __name__, url_prefix='/calendars')
+    bp.register_blueprint(
+      register_calendar(),
+    )
+    @bp.context_processor
+    async def inject_root():
+        # Must always return a dict
+        return {}
+
+    # ---------- Pages ----------
+
+    @bp.get("/")
+    @cache_page(tag="calendars")
+    async def home(**kwargs):
+        if not is_htmx_request():
+            html = await render_template(
+                "_types/calendars/index.html",
+            )
+        else:
+            html = await render_template(
+                "_types/calendars/_oob_elements.html",
+            )
+        return await make_response(html)
+
+
+    @bp.post("/new/")
+    @require_admin
+    @clear_cache(tag="calendars", tag_scope="all")
+    async def create_calendar(**kwargs):
+        form = await request.form
+        name = (form.get("name") or "").strip()
+
+        # Get post_id from context if available (blog-embedded mode)
+        post_data = getattr(g, "post_data", None)
+        post_id = (post_data.get("post") or {}).get("id") if post_data else None
+
+        if not post_id:
+            # Standalone mode: post_id from form (or None — calendar without post)
+            post_id = form.get("post_id")
+            if post_id:
+                post_id = int(post_id)
+
+        try:
+            await svc_create_calendar(g.s, post_id, name)
+        except Exception as e:
+            return await make_response(f'<div class="text-red-600 text-sm">{e}</div>', 422)
+
+        html = await render_template(
+            "_types/calendars/index.html",
+        )
+
+        # Blog-embedded mode: also update post nav
+        if post_data:
+            from ..post.services.entry_associations import get_associated_entries
+
+            cals = (
+                await g.s.execute(
+                    select(Calendar)
+                    .where(Calendar.post_id == post_id, Calendar.deleted_at.is_(None))
+                    .order_by(Calendar.name.asc())
+                )
+            ).scalars().all()
+
+            associated_entries = await get_associated_entries(g.s, post_id)
+
+            nav_oob = await render_template(
+                "_types/post/admin/_nav_entries_oob.html",
+                associated_entries=associated_entries,
+                calendars=cals,
+                post=post_data["post"],
+            )
+
+            html = html + nav_oob
+
+        return await make_response(html)
+    return bp