core: build rhai without ahash/runtime-rng

rhai's default feature set is ["std", "ahash/runtime-rng"]. The second half
seeds hash maps from OS entropy, which is a run-to-run variation source
living under a crate whose whole promise is byte-identical replays — and it
pulls getrandom, which has no backend on wasm32-unknown-unknown, so the
browser build could not compile at all.

Dropping it leaves ahash on its compile-time seed. The canonical Neon
Precinct playthrough produces byte-identical events before and after, and
the suite is green.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

Cargo.lock

@@ -16,7 +16,6 @@ checksum = "5a15f179cd60c4584b8a8c596927aadc462e27f2ca70c04e0071964a73ba7a75"
 dependencies = [
  "cfg-if",
  "const-random",
- "getrandom 0.3.4",
  "once_cell",
  "version_check",
  "zerocopy",
@@ -137,7 +136,7 @@ version = "0.1.16"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "f9d839f2a20b0aee515dc581a6172f2321f96cab76c1a38a4c584a194955390e"
 dependencies = [
- "getrandom 0.2.17",
+ "getrandom",
  "once_cell",
  "tiny-keccak",
 ]
@@ -274,18 +273,6 @@ dependencies = [
  "wasi",
 ]
 
-[[package]]
-name = "getrandom"
-version = "0.3.4"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "899def5c37c4fd7b2664648c28120ecec138e4d395b459e5ca34f9cce2dd77fd"
-dependencies = [
- "cfg-if",
- "libc",
- "r-efi",
- "wasip2",
-]
-
 [[package]]
 name = "glam"
 version = "0.27.0"
@@ -698,12 +685,6 @@ dependencies = [
  "proc-macro2",
 ]
 
-[[package]]
-name = "r-efi"
-version = "5.3.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "69cdb34c158ceb288df11e18b4bd39de994f6657d83847bdffdbd7f346754b0f"
-
 [[package]]
 name = "rhai"
 version = "1.25.1"
@@ -741,7 +722,7 @@ checksum = "a4689e6c2294d81e88dc6261c768b63bc4fcdb852be6d1352498b114f61383b7"
 dependencies = [
  "cc",
  "cfg-if",
- "getrandom 0.2.17",
+ "getrandom",
  "libc",
  "untrusted",
  "windows-sys",
@@ -1035,15 +1016,6 @@ version = "0.11.1+wasi-snapshot-preview1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "ccf3ec651a847eb01de73ccad15eb7d99f80485de043efb2f370cd654f4ea44b"
 
-[[package]]
-name = "wasip2"
-version = "1.0.4+wasi-0.2.12"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b67efb37e106e55ce722a510d6b5f9c17f083e5fc79afc2badeb12cc313d9487"
-dependencies = [
- "wit-bindgen",
-]
-
 [[package]]
 name = "wasm-bindgen"
 version = "0.2.126"
@@ -1212,12 +1184,6 @@ version = "0.52.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "589f6da84c646204747d1270a2a5661ea66ed1cced2631d546fdfb155959f9ec"
 
-[[package]]
-name = "wit-bindgen"
-version = "0.57.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1ebf944e87a7c253233ad6766e082e3cd714b5d03812acc24c318f549614536e"
-
 [[package]]
 name = "writeable"
 version = "0.6.3"

mrpci-core/Cargo.toml

@@ -11,7 +11,15 @@ image = { version = "0.24", default-features = false, features = ["png"] }  # PN
 # Room logic. "sync" keeps the engine Send+Sync (the HTTP surface shares
 # GameState across threads); "no_time" bans wall-clock from scripts, so a
 # replayed script is bit-identical — the whole CPU-speed-bug class, deleted.
-rhai = { version = "1", features = ["sync", "no_time"] }
+#
+# default-features = false drops exactly one thing from rhai's default set:
+# `ahash/runtime-rng`, which seeds hash maps from the OS entropy pool. We
+# want the compile-time seed instead — one less source of run-to-run
+# variation under a crate whose whole promise is byte-identical replays —
+# and it's also what makes wasm32-unknown-unknown build at all (runtime-rng
+# pulls getrandom, which has no default backend there). "std" is the rest of
+# rhai's default and stays on.
+rhai = { version = "1", default-features = false, features = ["std", "sync", "no_time"] }
 
 # Native-only: the HTTP surface and the AI parser lane don't exist in
 # browser builds (wasm gets the deterministic parser and bundles).