Test Quick with Lucee full null support

[elpete]

Closes #64

Issue review

Recommendation: 10/10 — implement. Full null support changes how database nulls are represented at Quick’s public boundaries, so exercising this mode in CI is a strong fit. It catches compatibility regressions that the default Lucee configuration necessarily hides. The tradeoff is one additional Lucee job per ColdBox matrix entry and null-mode-aware assertions where the two engine modes intentionally differ.

Implementation

• adds a dedicated Lucee 6 server profile with lucee.full.null.support=true
• adds that profile to PR, cron, and release test matrices
• verifies database null behavior through normal Quick entity getters, mementos, casts, relationships, saves, and qb query results
• centralizes full-null detection for integration specs
• keeps memento null-default behavior distinct from raw entity/query null behavior

Test-first evidence

The first full-null baseline reproduced seven failing assertions (and zero errors) where tests assumed Lucee would coerce database nulls to empty strings. The assertions were updated to validate each mode’s intentional public behavior.

Validation

• Lucee 6 full-null suite: 495 passed, 0 failed, 0 errors, 3 skipped
• Lucee 6 standard suite: 495 passed, 0 failed, 0 errors, 3 skipped
• box run-script format
• git diff --check

Uses qb@14.0.0-beta.3.