fix: Patch coarsetime for MIPS AtomicU64 support

- Vendor coarsetime crate with portable-atomic fallback
- Use portable-atomic on targets without 64-bit atomics
- Patch crates.io to use local coarsetime
- Fixes MIPS build failure (AtomicU64 missing)

Cargo.lock

@@ -477,10 +477,9 @@ checksum = "c3e64b0cc0439b12df2fa678eae89a1c56a529fd067a9115f7827f1fffd22b32"
 [[package]]
 name = "coarsetime"
 version = "0.1.37"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e58eb270476aa4fc7843849f8a35063e8743b4dbcdf6dd0f8ea0886980c204c2"
 dependencies = [
  "libc",
+ "portable-atomic",
  "wasix",
  "wasm-bindgen",
 ]
@@ -2278,6 +2277,12 @@ version = "0.3.32"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7edddbd0b52d732b21ad9a5fab5c704c14cd949e5e9a1ec5929a24fded1b904c"
 
+[[package]]
+name = "portable-atomic"
+version = "1.13.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c33a9471896f1c69cecef8d20cbe2f7accd12527ce60845ff44c153bb2a21b49"
+
 [[package]]
 name = "potential_utf"
 version = "0.1.4"