feat: close stage 0-2 audit groundwork

Remove legacy SDL/OpenGL adapters from the workspace and introduce winit/Vulkan adapter boundaries for the rendered composition root.

Add reproducible toolchain and xtask CI coverage for formatting, tests, clippy, docs, policy, deny, acceptance auditing, and hosted OS matrix evidence.

Strengthen Stage 1 data contracts with byte-first paths, VFS hardening, structured diagnostics, RsLi writer/edit scaffolding, corpus reporting, and resource error classification.

Advance Stage 2 asset preparation by moving mission loading through assets/runtime boundaries, materializing prototype graph data, preserving provenance, and adding inspection/viewer integration.

Record the Stage 0-2 audit input, acceptance roadmap, coverage updates, and documentation notes for follow-up evidence.

docs/tomes/07-implementation.md

@@ -34,7 +34,7 @@ behavior         unit state machines, target and path requests
 physics          control systems, collision proxies and contacts
 animation        pose sampling, hierarchy and blending
 audio            sample cache, sources, listener and buses
-render           legacy-state compatibility and modern backend
+render           immutable frame contracts and modern backend
 network          game message schema plus transport adapters
 tools            validators, extractors, viewers, captures and editors
 ```
@@ -103,8 +103,8 @@ CPU assets и GPU resources имеют отдельные бюджеты и от
 
 ### Backend adapters
 
-Render, audio, input и network получают отдельные adapters. Legacy compatibility
-state живёт выше Vulkan, D3D11 или Metal backend; DirectPlay compatibility живёт
+Render, audio, input и network получают отдельные adapters. Compatibility state
+живёт вне Vulkan, D3D11 или Metal backend; DirectPlay compatibility живёт
 отдельно от modern transport. Так можно заменить платформу, не меняя форматы,
 игровую семантику и regression corpus.