Phase 2: LTI plumbing, roster sync, and fake-launch dev mode

OIDC login, launch, and JWKS endpoints built on pylti1p3next's Flask
adapter, with launch-claim processing split into a testable module.
Instructor launches refresh the roster through NRPS; the sync code is
source-agnostic and also drives the dev-mode fake roster. Dev mode
(COLDCALL_DEV_MODE=1) provides fake instructor and student personas
that set up the same session state as a real launch, so the rest of
the app can be developed before a Canvas Developer Key exists.

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

tests/test_launch.py

@@ -0,0 +1,51 @@
+from coldcall_lti import launch, models
+
+
+def sample_launch_data(is_instructor=False):
+    roles = [launch.ROLE_INSTRUCTOR] if is_instructor else [launch.ROLE_LEARNER]
+    return {
+        "sub": "canvas-user-42",
+        "name": "Pat Example",
+        "email": "pat@example.edu",
+        "picture": "https://example.edu/pat.png",
+        launch.CLAIM_DEPLOYMENT: "dep-1",
+        launch.CLAIM_CONTEXT: {"id": "ctx-abc", "title": "COM 999"},
+        launch.CLAIM_ROLES: roles,
+    }
+
+
+def test_extract_launch_info_student():
+    info = launch.extract_launch_info(sample_launch_data())
+    assert info.context_id == "ctx-abc"
+    assert info.course_title == "COM 999"
+    assert info.user_id == "canvas-user-42"
+    assert info.deployment_id == "dep-1"
+    assert not info.is_instructor
+
+
+def test_extract_launch_info_instructor():
+    info = launch.extract_launch_info(sample_launch_data(is_instructor=True))
+    assert info.is_instructor
+
+
+def test_upsert_launch_creates_and_is_idempotent(db_session):
+    info = launch.extract_launch_info(sample_launch_data())
+    course, student = launch.upsert_launch(db_session, info)
+    assert course.title == "COM 999"
+    assert student.canvas_user_id == "canvas-user-42"
+
+    course2, student2 = launch.upsert_launch(db_session, info)
+    assert course2.id == course.id
+    assert student2.id == student.id
+    assert db_session.query(models.Enrollment).count() == 1
+
+
+def test_upsert_launch_reactivates_dropped_enrollment(db_session):
+    info = launch.extract_launch_info(sample_launch_data())
+    course, student = launch.upsert_launch(db_session, info)
+    enrollment = db_session.query(models.Enrollment).one()
+    enrollment.active = False
+    db_session.flush()
+
+    launch.upsert_launch(db_session, info)
+    assert db_session.query(models.Enrollment).one().active