docs(App): drop/update outdated {OC, OCP}\AppFramework\App docblocks

[joshtrichards]

Summary

• Updates OCP class and method-level docs for clarity and accuracy
• Updates OC class and method-level docs for clarity and accuracy
• Removes outdated and no longer applicable explanations throughout both classes
• Removes outdated examples (which better belong in Dev Manual anyhow).

TODO

• I'm not sure, but I think maybe OCP\AppFramework\App::dispatch() could/should be deprecated and/or better documented (from what I can tell it was part of the old approach to adding controller routes in routes.php unless I'm thinking about this entirely wrong).

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