[janmejai2002]

Description

This PR improves unit test coverage and assertions for two core SQLModel APIs:

1. sqlmodel_update() method contracts:

   • tests/test_update.py previously invoked org.sqlmodel_update(...) without asserting the updated field values or verifying that the method returns self.
   • Adds concrete assertions verifying that sqlmodel_update() updates model attributes, preserves unmodified fields, and adheres to the fluent return contract (assert result is org).
   • Adds test coverage for dictionary updates (sqlmodel_update({"name": ...})), ensuring non-model keys in dictionaries or updates are safely ignored without polluting attributes.
   • Adds validation coverage asserting that ValueError is raised when unsupported types (non-dict, non-BaseModel) are passed to sqlmodel_update().

2. Session.exec() non-scalar queries and bulk updates:

   • Session.exec() distinguishes between SelectOfScalar (which unwraps scalars) and standard Select / UpdateBase queries (which return tuples or CursorResult).
   • Unit tests in tests/test_query.py previously only covered single-model scalar selects (select(Hero)).
   • Adds unit test cases verifying:
     • session.exec(select(Hero.id, Hero.name)) properly returns row tuples ((hero.id, "Deadpond")).
     • session.exec(update(Hero)...) returns a valid CursorResult with expected .rowcount == 1.

---

Verification

• Tests: Ran pytest tests/test_update.py tests/test_query.py -v: 7 passed in 0.12s.
• Linter: Ran ruff check and ruff format --check: all checks passed, 0 errors.
• Dependencies & Mocks: Zero synthetic mocks. Uses standard SQLite engine and native SQLModel / SQLAlchemy types.

[YuriiMotov]

@janmejai2002, please stop ignoring contribution guidelines and PR template (I already warned you here).
If you keep ignoring rules, we will have to ban you