[Week7 - jbk] Task1: Add endpoints and input validation

[Candyroom136]

Summary

• Add missing CRUD endpoints: DELETE /notes/{id}, DELETE /action-items/{id}, GET /action-items/{id}
• Add input validation using Pydantic Field constraints (min_length, max_length)
• Add query parameter validation for skip (ge=0) and limit (ge=1, le=200)

Problem

The existing API was missing DELETE endpoints for both resources and a single-item GET for action items. Input validation was absent — empty strings and negative pagination values were accepted without error.

Approach

• Used Pydantic Field(...) with min_length/max_length to enforce non-empty inputs at the schema level
• Added ge/le constraints on skip and limit query parameters
• DELETE endpoints return 204 No Content on success, 404 if not found
• Followed existing code patterns (HTTPException for 404, db.flush() for persistence)

Testing

$ make test
3 passed in 0.04s
All existing tests pass. New endpoints follow the same error handling patterns already covered by tests.

Tradeoffs & Follow-ups

• Did not add dedicated tests for the new endpoints or validation errors (covered in Task 4)
• max_length=200 for title matches the DB column constraint (String(200)) but could be surfaced as a friendlier error message
• DELETE is a hard delete, not soft delete — no undo capability