coordination: claim static M2 batch materializer

coordination/claims/M03-RND-M2-STATIC-BATCH-MATERIALIZER-001.md

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+# M03-RND-M2-STATIC-BATCH-MATERIALIZER-001
+
+<!-- OPENWC_CLAIM:M03-RND-M2-STATIC-BATCH-MATERIALIZER-001:sindo-main-codex:2026-07-20 -->
+
+## Owner
+
+- Agent ID: `sindo-main-codex`
+- Target: M03 Renderer Facade and Safe Extraction
+- Branch: `work/sindo-main-codex/m03-m2-static-batch-materializer`
+- Worktree: `C:\Users\sindo\open-wc-worktrees\m03-m2-static-batch-materializer`
+
+## Outcome
+
+Extract main-thread static M2 `MultiMesh` construction, render-property setup
+and batch attachment from `StreamingWorldLoader`.
+
+## Non-goals
+
+- Change M2 grouping, batch sizing, build cursors, budgets or retry behavior.
+- Change Mesh loading, refresh, cache ownership or missing-model outcomes.
+- Own animated M2 instances, Editor persistence or tile cleanup.
+- Introduce spatial cells or change transform order, visibility or shadows.
+
+## Paths
+
+- Exclusive: `src/render/m2/m2_static_batch_materializer.gd`,
+  `src/tools/verify_m2_static_batch_materializer.gd`,
+  `docs/modules/m2-static-batch-materializer.md`, this claim
+- Shared/hotspots: `src/scenes/streaming/streaming_world_loader.gd`, M2 build/
+  Mesh-cache/facade/internal-access/manifest verifiers and specs,
+  `docs/modules/world-renderer.md`, `docs/modules/README.md`, `RENDER.md`,
+  `targets/03-renderer-facade.md`
+- Generated/ignored: `.godot`, native DLL, generated resources/caches and proprietary corpus
+
+## Contracts and data
+
+- `MultiMesh.TRANSFORM_3D`, exact Mesh identity, instance count and transform
+  slice order remain unchanged.
+- Batch node name remains model basename plus serial.
+- Visibility end/margin and shadow setting remain exact renderer inputs.
+- A valid batch attaches once to the supplied M2 parent and returns its node.
+- Loader retains Editor-owner assignment, build cursor, budgets and retries.
+
+## Dependencies
+
+- Requires: accepted animated materializer package on master `86814de`
+- Blocks: further M2 build-job orchestration extraction
+- External state: Godot MultiMesh and SceneTree mutation remain main-thread APIs
+
+## Verification
+
+- Commands: dedicated invalid/name/mesh/count/order/render/attachment/source/timing
+  verifier; M2 build/cache/prototype/animated/shutdown/material/facade/internal-
+  access/manifest regressions; docs/coordination/dry-run gates
+- Fixtures: synthetic ArrayMesh and ordered Transform3D slices
+- Fidelity evidence: exact existing MultiMesh construction and render settings
+- Performance budget: materialize 10,000 transforms under one second
+
+## Documentation deliverables
+
+- Inline API docs
+- Module spec with inputs/outputs, ownership and source map
+- Data-flow, lifecycle/state, sequence and dependency diagrams
+- Adjacent build/cache/world-renderer/module-registry/RENDER updates
+
+## Simplicity and naming
+
+- Important name introduced: `M2StaticBatchMaterializer`
+- Simplest solution: synchronous main-thread RefCounted returning attached node
+- Rejected complexity: signals, async queue, callbacks and generic materializer base
+- Unavoidable complexity: MultiMesh is a Godot Resource owned through its node
+- Measured optimization evidence: bounded synthetic transform upload
+
+## Status
+
+- State: active
+- Done: contract and ownership boundary
+- Next: implementation, verification and documentation
+- Blocked by:
+
+## Handoff
+
+- Commit:
+- Results:
+- Remaining risks:
+- Documentation updated:
+