fix: Reset traits state on chapter change

[opencode-agent]

Implemented Option 1 (central reset_chapter_traits() helper).

Changes:

• scripts/scr_ChapterTraits/scr_ChapterTraits.gml: added reset_chapter_traits() next to setup_chapter_traits() - clears obj_creation.chapter_trait_meta and sets all activated = false on all_advantages / all_disadvantages.
• scripts/scr_chapter_new/scr_chapter_new.gml: call reset_chapter_traits() at top of scr_chapter_new() before points recompute, keeping existing _adv.add() loop for the new chapter.
• scripts/scr_chapter_random/scr_chapter_random.gml: call reset_chapter_traits() alongside points = 0 reset so blank/random custom starts clean.

This keeps points accounting single-owner (recomputed, not incrementally adjusted) and prevents stale meta from disabling traits on later screens.

Suggested commit (repo pattern fix: ...):
fix: reset chapter traits on chapter select

Closes #1567

github run

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Summary by cubic

Fixes stale chapter traits carrying over between selections so picking a new chapter no longer leaves old traits activated or disables traits on later screens.

• Adds reset_chapter_traits() to clear chapter_trait_meta and set all advantages and disadvantages to activated = false.
• Calls it when a chapter icon is selected and when a blank/random chapter is created, before points are recomputed.

^{Written for commit b210bee. Summary will update on new commits.}

[EttyKitty]

/review

[lyra-the-bot]

LGTM. Central reset_chapter_traits() correctly clears the two pieces of stale state that caused #1567 (activated flags + chapter_trait_meta, which drives disable()). Both call sites reset before points are recomputed/re-assigned, so no double-counting, and the existing _adv.add() loop re-populates meta/points for the new chapter. Verified scr_initialize_custom and role-ban logic consume only activated, so the reset fully covers downstream state.