feat(conversions): end-to-end PPT/PPTX/ODP -> PDF pipeline with RQ worker + Gotenberg

DB/model

Add Conversion model + ConversionStatus enum (pending, processing, ready, failed)
Alembic migrations: create conversions table, indexes, unique (source_event_media_id, target_format, file_hash), and NOT NULL on file_hash
API

Enqueue on upload (ppt|pptx|odp) in routes/eventmedia.py: compute sha256, upsert Conversion, enqueue job
New routes:
POST /api/conversions/<media_id>/pdf — ensure/enqueue conversion
GET /api/conversions/<media_id>/status — latest status/details
GET /api/files/converted/<path> — serve converted PDFs
Register conversions blueprint in wsgi
Worker

server/worker.py: convert_event_media_to_pdf
Calls Gotenberg /forms/libreoffice/convert, writes to server/media/converted/
Updates Conversion status, timestamps, error messages
Fix media root resolution to /server/media
Prefer function enqueue over string path; expose server.worker in package init for RQ string compatibility
Queue/infra

server/task_queue.py: RQ queue helper (REDIS_URL, default redis://redis:6379/0)
docker-compose:
Add redis and gotenberg services
Add worker service (rq worker conversions)
Pass REDIS_URL and GOTENBERG_URL to server/worker
Mount shared media volume in prod for API/worker parity
docker-compose.override:
Add dev redis/gotenberg/worker services
Ensure PYTHONPATH + working_dir allow importing server.worker
Use rq CLI instead of python -m rq for worker
Dashboard dev: run as appropriate user/root and pre-create/chown caches to avoid EACCES
Dashboard dev UX

Vite: set cacheDir .vite to avoid EACCES in node_modules
Disable Node inspector by default to avoid port conflicts
Docs

Update copilot-instructions.md with conversion system: flow, services, env vars, endpoints, storage paths, and data model

server/alembic/versions/2b627d0885c3_merge_heads_after_conversions.py

@@ -0,0 +1,28 @@
+"""merge heads after conversions
+
+Revision ID: 2b627d0885c3
+Revises: 5b3c1a2f8d10, 8d1df7199cb7
+Create Date: 2025-10-06 20:27:53.974926
+
+"""
+from typing import Sequence, Union
+
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision: str = '2b627d0885c3'
+down_revision: Union[str, None] = ('5b3c1a2f8d10', '8d1df7199cb7')
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    """Upgrade schema."""
+    pass
+
+
+def downgrade() -> None:
+    """Downgrade schema."""
+    pass