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/versions/487d155678ea_course_term_dates.py

@@ -0,0 +1,32 @@
+"""course term dates
+
+Revision ID: 487d155678ea
+Revises: 1ec230be46bd
+Create Date: 2026-07-31 16:50:52.938563
+
+"""
+from typing import Sequence, Union
+
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision: str = '487d155678ea'
+down_revision: Union[str, None] = '1ec230be46bd'
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.add_column('courses', sa.Column('start_date', sa.Date(), nullable=True))
+    op.add_column('courses', sa.Column('end_date', sa.Date(), nullable=True))
+    # ### end Alembic commands ###
+
+
+def downgrade() -> None:
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.drop_column('courses', 'end_date')
+    op.drop_column('courses', 'start_date')
+    # ### end Alembic commands ###