Ship the native Rust map-editing MVP

[zoeyrose]

Important

This preserved authoring issue now belongs to the fresh MIT Rust editor under the replacement program. Gameplay/content design and safe-authoring requirements remain unchanged. Legacy implementation paths below are historical evidence.

Replacement implementation contract

Deliver the product MVP through the fresh Rust editor, released content-toolkit document/transaction crates, and shared renderer. Preserve the complete authoring workflow and safety gates; replace classic C/GCC/MinGW/Java/Gridarta integration details with Cargo, Clippy, Rust tests, and Linux/Windows packages.

Verified original past contributions by an approved MIT provenance grantor may be copied, migrated, translated, or relicensed under MIT only after complete Git provenance and third-party-material review is recorded. Other GPL implementation/tests must not be mechanically ported.

Required verification

• Preserve unknown fields, comments, ordering, and untouched bytes through lossless toolkit transactions.
• Use semantic commands with revision preconditions, dry-run/diff, undo/recovery, validation, and atomic writes.
• Use the exact shared renderer and toolkit APIs; no duplicate parser, renderer, or pixel-selection path.
• Test Linux/Windows, malformed/large projects, external edits, storage/device failures, and wrapper-isolated playtests as applicable.

Preserved product/design specification and historical implementation notes

Parent and roadmap

• Parent tracker: Replace Gridarta with the standalone MIT Rust editor #13
• Roadmap: Roadmap: replace classic Atrinik with a fresh MIT Go and Rust stack atrinik#168
• Roadmap milestone: M3
• Prerequisites: Content tooling: build the lossless core and safe headless CLI content#14, Integrate lossless authored documents with the shared renderer #12

Outcome

Ship installable Linux and Windows atrinik-editor targets that provide the complete safe map-editing loop on the shared content and renderer cores.

Scope

• Add project/map open, recent files, multi-map tabs, tiled-neighbor navigation, and exact pan/zoom isometric preview.
• Implement palette search/previews, selection, paint/erase/eyedropper/move/rectangle/fill/copy/paste/direction tools, and stacked-depth/layer visibility.
• Add object/inventory tree, schema-driven inspector with raw lossless fallback, inline diagnostics, undo/redo, dirty state, autosave/recovery, and diff-before-save.
• Package the editor against explicit local assets without a bundled server/client copy or Java.

Superseded path / cleanup target

Do not embed editor state or filesystem authoring in the connected client. Remove MVP-era stubs and copied UI/render logic before acceptance.

Acceptance criteria

• A map maker can open, edit, validate, save, reopen, undo, and redo a representative map with minimal diffs.
• Unknown fields, comments, nested inventory, authored order, and attribution survive the workflow.
• Viewport output matches the connected client for representative scenes.
• Linux and Windows packages start and edit maps without Java/Gridarta or mutable source-tree runtime setup.

Validation baseline

Before: the supported tree has no native maintained map editor and relies on downloaded Gridarta-era tooling.

After: a usable native map editor performs the core authoring loop through shared APIs.

Run editor model tests, startup/open/edit/save/reopen/undo/redo smoke tests, visual fixtures, package checks, and GCC/Clang/MinGW builds.

This issue is a bounded child of #13. The parent remains open until every sibling child is complete.