Phase 5: reporting, exports, pronouns, and roster freshness

Instructor participation report: per-student histograms, outcome mix
by class day, and a sortable table including the fairness ratio
(answered calls over questions present for, with opt-out days out of
the denominator), plus CSV exports of students, calls, and opt-outs.

Assessment scales are now per-course data: ordered levels with labels
and points out of 100 (defaults carry the old R grading values), with
calls referencing levels by id so renames follow through to history.
Renaming, re-pointing, reordering, and adding levels are always
allowed; deleting a level in use by recorded calls is blocked.

Pronouns and course term dates come from Canvas custom variable
substitutions, at launch and roster-wide via rlid-scoped NRPS; the
student page notes that names/pronouns are Canvas-sourced. Rosters
can also be refreshed outside launches: a "Sync roster now" button
and a sync-rosters CLI command for an hourly cron job, skipping ended
courses. Alembic now runs SQLite-compatible batch migrations with a
constraint naming convention.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

migrations/env.py

@@ -49,6 +49,9 @@ def run_migrations_offline() -> None:
         target_metadata=target_metadata,
         literal_binds=True,
         dialect_opts={"paramstyle": "named"},
+        # SQLite cannot ALTER constraints in place; batch mode uses the
+        # copy-and-move strategy and is harmless on MariaDB/MySQL.
+        render_as_batch=True,
     )
 
     with context.begin_transaction():
@@ -70,7 +73,9 @@ def run_migrations_online() -> None:
 
     with connectable.connect() as connection:
         context.configure(
-            connection=connection, target_metadata=target_metadata
+            connection=connection,
+            target_metadata=target_metadata,
+            render_as_batch=True,
         )
 
         with context.begin_transaction():