feat(rendering): Vendor Bevy rendering crates (Phase 1 complete)

Closes #6, #7, #8, #9, #10
Refs #2, #122

Vendored bevy_render, bevy_core_pipeline, and bevy_pbr from Bevy v0.17.2
(commit 566358363126dd69f6e457e47f306c68f8041d2a) into libmarathon.

- ~51K LOC vendored to crates/libmarathon/src/render/
- Merged bevy_render_macros into crates/macros/
- Fixed 773→0 compilation errors
- Updated dependencies (encase 0.10→0.11, added 4 new deps)
- Removed bevy_render/pbr/core_pipeline from app Cargo features

All builds passing, macOS smoke test successful.

Signed-off-by: Sienna Meridian Satterwhite <sienna@r3t.io>

Cargo.toml

@@ -1,5 +1,5 @@
 [workspace]
-members = ["crates/libmarathon", "crates/sync-macros", "crates/app", "crates/xtask"]
+members = ["crates/libmarathon", "crates/macros", "crates/app", "crates/xtask"]
 resolver = "2"
 
 [workspace.package]