refactor: Add strict property/parameter typing to OCP\HintException

[joshtrichards]

• Resolves: #

Summary

Changes:

• Added declare(strict_types=1)
• Typed constructor params:
• Typed property with constructor property promotion
• Simplified getHint() to a direct string check

Why:

• Stronger static analysis
• Clearer public API contract
• Less boilerplate
• Same runtime behavior for valid callers

TODO

• ...

Checklist

• Code is properly formatted
• Sign-off message is added to all commits
• Tests (unit, integration, api and/or acceptance) are included
• Screenshots before/after for front-end changes
• Documentation (manuals or wiki) has been updated or is not required
• Backports requested where applicable (ex: critical bugfixes)
• Labels added where applicable (ex: bug/enhancement, 3. to review, feature component)
• Milestone added for target branch/version (ex: 32.x for stable32)

AI (if applicable)

• The content of this PR was partly or fully generated using AI (yes, but manually reviewed)