Add textured W3D model previews in completion docs

[ViTeXFTW]

Summary

• Add a new zerosyntax-w3d crate to parse W3D files and render thumbnail previews for model completions.
• Upgrade Model = completions to resolve on demand and show a textured preview when the indexed model and textures are available.
• Add preview settings for image width and zoom, plus cache invalidation when preview settings or the index change.
• Thread asset URIs through indexing so preview rendering can resolve textures from packed assets and workspace files.
• Update docs and the VS Code extension to expose the new preview behavior and settings.

Testing

• cargo test -p zerosyntax-analysis --test spec
• cargo test -p zerosyntax-analysis
• cargo test -p zerosyntax-server
• cargo test -p zerosyntax-schema
• python crates/server/tests/e2e.py target/debug/zerosyntax-lsp.exe
• Not run: full corpus gate (cargo test --release -p zerosyntax-analysis --test corpus -- --ignored --nocapture)

[greptile-apps]

Greptile Summary

Adds textured W3D model previews to completion documentation.

• Introduces bounded W3D parsing and thumbnail rendering.
• Resolves model completions lazily and caches generated previews.
• Preserves filename fallback models on parse failures.
• Invalidates preview cache entries when settings or indexes change.
• Exposes preview width and zoom settings through the VS Code extension.

Confidence Score: 5/5

The follow-up changes appear safe to merge.

No blocking failure remains in the fixes associated with the previous review threads.

T-Rex Logs

What T-Rex did

• Reviewed the locked build log to confirm the exact build command, the working directory, the command output, and that the exit code was 0.
• Reviewed the after-harness log to verify the harness command and that textured PNG resolution, preview size/zoom hot reload, loose/base assets, BIG archives, and the remaining LSP regression flow passed as expected.

_{Ran code and verified through T-Rex}

Important Files Changed

Filename	Overview
crates/server/src/scan.rs	The parse-failure fix preserves the trimmed filename fallback model and is covered by a focused regression test.
crates/w3d/src/render.rs	Rendering now enforces triangle, texture, decoded-pixel, and raster-work limits for completion previews.
crates/server/src/backend.rs	Generation-aware cache insertion prevents in-flight renders from repopulating invalidated preview entries.

_{Reviews (2): Last reviewed commit: "fix: harden W3D preview processing" | Re-trigger Greptile}

[ViTeXFTW]

@greptileai