fix: complete Version 2.0.12 integration hardening

[sanskarIN]

Purpose

Finish the final Version 2.0.12 integration pass on the current main base instead of relying on older Custom Game Builder CI evidence from the former Version 1.5 line.

Product fixes and polish

• add saved custom-preset Edit workflow;
• support safe preset rename while rejecting collisions with a different saved preset;
• add Duplicate workflow with a bounded, case-insensitively unique copy name;
• keep duplication unsaved until explicit Save;
• add Cancel edit and restore the default creation form;
• replace cramped trailing saved-preset icon rows with a compact action menu;
• fix loaded selector state with value-dependent FormField keys;
• return Edit/Duplicate actions directly to the form without forcing focus or opening the keyboard;
• localize new action labels/messages in English and Hindi;
• preserve all existing custom-session trust, reset, replacement, import, and per-mode-record isolation rules.

Regression coverage

• edit/rename/config preservation;
• visible selector-state refresh;
• edit-name collision rejection;
• duplicate workflow and storage behavior;
• cancel-edit behavior;
• Edit/Duplicate action-to-form navigation and immediate hit testing;
• confirmed deletion through the action menu;
• narrow 320×640 layout with 2× text scaling;
• Hindi preset-action labels;
• existing save/play/invalid-seed flows;
• public/canonical documentation navigation and current-release evidence boundaries.

Documentation completed

• expose Custom Game Builder in the public root README;
• rewrite docs/CUSTOM_GAME_BUILDER.md for current 2.0.12+2012 behavior;
• archive docs/VERSION_1_6_ROADMAP.md as historical instead of current;
• add docs/FINAL_2_0_12_INTEGRATION_AUDIT.md explaining the same-commit verification gap;
• add architecture walkthrough, error/diagnosis reference, contributor tutorial, documentation audit checklist, and Linux native-toolchain handbook;
• integrate all final guides into docs/README.md and docs/setup/README.md;
• expand docs/USER_GUIDE.md and docs/FEATURE_REFERENCE.md with the complete custom-game workflow/trust model;
• update CHANGELOG.md and what_changed.md;
• preserve Phase 33 continuity in what_changed_archive_phase_33.md;
• expand documentation regression protection.

Repository hygiene

• obsolete conflicting documentation PR Docs/phase 33 complete documentation #24 was closed as superseded after its useful content was carried forward here;
• final stale-text and unresolved-marker searches found no current obsolete Version 1.6/1.5/stable-1.0 wording and no current TODO/FIXME/HACK/unimplemented marker requiring source work;
• issue Repository settings: protect main and require CI before merge #12 remains open because it concerns GitHub repository settings. main now reports protected, but the available connector cannot inspect/write the underlying ruleset or prove intended required CI contexts.

Evidence rule

The earlier Custom Game Builder PR passed formatter/analyzer/tests/Web/native builds on an older 1.5.0+15 base. Those results remain historical feature evidence and are not relabeled as current Version 2.0.12+2012 evidence.

This PR must pass the maintained CI quality job and configured Platform Builds matrix on its exact final head before merge. Dependency Review is path-filtered to dependency/Android/workflow-sensitive files and is not expected for this PR because none of those files changed.

Release boundary

This source work does not change or fabricate the genuine manual release-qualification status. Stable promotion remains fail-closed at the canonical 0/13 real-world evidence boundary until those checks are actually performed.