fix: backend-lint and backend-test CI (#35)

[baohuy1303]

Fix: backend-lint and backend-test CI

Fixes both backend-lint and backend-test jobs. All checks and tests now pass on this branch.

Note: frontend-lint and frontend-build failures are tracked and fixed in separate issues/PRs.

Closes #35

What was done

Lint fixes (six phases, one commit each):

Phase	What
1	ruff format src/ repo-wide (formatter version skew)
2	ruff check --fix (import order, unused imports, py312 modernizations)
3	Remaining ruff errors by hand (E501, E741, E731, F841, UP042)
4	Added type arguments to bare generics (143 type-arg errors)
5	Annotated untyped function signatures (no-untyped-def, no-untyped-call)
6	Resolved remaining mypy errors (arg-type, attr-defined, union-attr, etc.)

Phase 6 also fixed two real bugs found during type review: missing lms_adapter in courses.py and a wrong return tuple in outcome_tracker.py.

Test fixes:

Test	Fix
test_llm_stream.py (2)	Fixed OpenAI mock to be a coroutine returning an async generator, matching the real openai library interface
test_invalid_name_fails	Updated assertion for Pydantic V2 error format (string_too_short vs min_length)
test_non_pedagogical_template_fails	Updated assertion to match actual validator error messages
test_unsafe_content_fails	Fixed NameError (invalid_strategy should be unsafe_strategy)
test_preprocess_template	Added missing stop words (you, are, is, etc.) to _preprocess_template

Verification

ruff check src/           # All checks passed!
ruff format --check src/  # 99 files already formatted
mypy src/                 # Success: no issues found in 99 source files
pytest tests/             # 160 passed

[Youdahe123]

Solid, methodical CI fix. The phased approach (formatter → auto-fixes → manual → generics → signatures → mypy) is the right order and makes the diff reviewable. Key observations:

What's solid:

• The two real bugs caught during type review (missing lms_adapter in courses.py, wrong return tuple in outcome_tracker.py) are a good sign — mypy found things that tests missed.
• OpenAI mock fix (coroutine returning async generator) is the correct interface match for the real library.
• Pydantic V2 error format update (string_too_short vs min_length) and the NameError fix in test_unsafe_content_fails are clean.
• 160 tests passing with no new skips or xfails.

Minor notes:

• pyproject.toml added 3 lines — worth confirming none of these relax rules we'd want enforced (e.g., ignore directives in mypy config). Quick sanity check before merge.
• tasks/lms_sync.py was heavily changed (+118/-27). The changes appear to be type annotation additions, but given it drives background sync jobs, worth a quick read to confirm no behavioral changes snuck in alongside the type fixes.

CI: Backend lint + tests pass ✅. Frontend lint/build fail — those are tracked and fixed in #38 (separate PR).

✅ Approving — backend side is clean. Suggest merging before #38 since #38 is likely branched from a state that doesn't include these backend fixes yet.

[Youdahe123]

Merge status

CI: Backend lint ✅ Backend tests ✅ | Frontend lint ❌ Frontend build ❌ (frontend failures are pre-existing, fixed in #38)

Recommendation: merge this first.

This is the only PR in the stack that can land without a rebase — backend CI is clean on its own run. Frontend failures here are not caused by this branch; they predate it and are resolved by #38.

After this merges: #38 should rebase onto updated main to pick up these backend fixes. Once it does, all 4 CI checks should pass on #38.

Merge order: #36 → #38 → #34