docs(agents): add Integration Test phase to org-standard workflow

[yeongseon]

Motivation

Two recent releases shipped without real-DB validation. This change makes integration testing a mandatory phase, not a follow-up.

sqlalchemy-cubrid v1.2.0 and pycubrid v1.1.0 both shipped to PyPI with new features tested only via mocks — never against a live CUBRID instance. This PR patches that gap in the development process.

What Changed

• 4-phase → 5-phase workflow cycle
• New Phase 4: Integration Test against real CUBRID — live-DB validation via the repo's Docker setup or CI integration matrix is now mandatory
• Harder skip language: Phase 4 is NEVER skippable for any change that touches runtime code paths; trivial/doc-only changes may skip phases 1, 4, and 5; all skips must be recorded in the PR description

Diff Highlights

-All non-trivial work across cubrid-labs repositories MUST follow this 4-phase cycle:
+All non-trivial work across cubrid-labs repositories MUST follow this 5-phase cycle:

 1. Oracle Design Review
 2. Implementation
 3. Documentation Update
+4. Integration Test against real CUBRID — Mock-only validation is INSUFFICIENT. No release may proceed until integration jobs are green.
 5. Oracle Post-Implementation Review (was 4)

-Skipping any phase requires explicit justification. Trivial changes (typos, single-line fixes) may skip phases 1 and 4.
+Skipping any phase requires explicit justification recorded in the PR description. Trivial changes (typos, single-line fixes, doc-only edits) may skip phases 1, 4, and 5. Phase 4 is NEVER skippable for any change that touches runtime code paths.

This is the canonical change

This cubrid-cookbook-python PR is the canonical reference. All 11 other cubrid-labs repositories receive the identical change, cross-referencing this PR.