chore: rebrand 'Softcore' to 'Casual'

[Chew]

Goes with RetroAchievements/RAWeb#5015

Changes all instances of "softcore" to "casual". "Mode" was also added to help with flow, ideally all instances of hardcore/casual have a "mode" appended for clarity, this at least fixes the "casual" to be qualified with "mode".

In the Glossary, Softcore was moved to Casual, with a note that it was formerly known as Softcore. This is the only remaining instance of the term in the docs.

[greptile-apps]

Confidence Score: 5/5

Documentation-only rebrand; no functional code changed.

All "softcore" occurrences replaced consistently; anchor links verified intact; only intentional legacy mention remains in the glossary.

No files require special attention.

_{Reviews (2): Last reviewed commit: "Update docs/general/faq.md" | Re-trigger Greptile}

[wescopeland]

@greptileai specifically: find any remaining softcore branding in the documentation

[greptile-apps]

Based on a full search of the repository, there were 10 files containing "softcore" — and the PR addresses all 10 of them:

File	Status
docs/general/glossary.md	✅ Updated — one intentional instance remains: "formerly known as Softcore"
docs/orphaned/load-state-feature.md	✅ Fully updated
docs/general/faq.md	✅ Fully updated
docs/general/hardcore-compliance-requirements.md	✅ Fully updated
docs/developer-docs/why-delta.md	✅ Fully updated
docs/general/events.md	✅ Fully updated
docs/general/standalone-support.md	✅ Fully updated
docs/guidelines/users/global-leaderboard-and-achievement-hunting-rules.md	✅ Fully updated
docs/general/emulator-support-and-issues.md	✅ Fully updated
docs/developer-docs/save-and-password-protection.md	✅ Fully updated

The only remaining "Softcore" after this PR merges will be the intentional historical reference in the glossary: "Casual, formerly known as Softcore" — which is by design as noted in the PR description.

The rebrand looks complete. No missed instances.

[wescopeland]

ok

[wescopeland]

Thanks!