fix: patch core2 0.4.0 via git mirror to unblock wasm sub-build resolution

core2 0.4.0 was yanked from crates.io. Wasm runtime builds invoke cargo
as a subprocess without --locked, causing fresh dependency resolution to
fail when selecting core2 ^0.4 (no non-yanked version available).

The dependency path: pezsc-network -> cid v0.9.0 -> core2 ^0.4

Adding a git mirror at git.pezkuwichain.io/pezkuwichain/core2 as a
workspace [patch.crates-io] entry. The wasm-builder propagates workspace
patches to the generated wbuild Cargo.toml, so the sub-build resolves
core2 from the git source instead of the yanked crates.io version.

Cargo.lock

@@ -3317,8 +3317,7 @@ checksum = "773648b94d0e5d620f64f280777445740e61fe701025087ec8b57f45c791888b"
 [[package]]
 name = "core2"
 version = "0.4.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b49ba7ef1ad6107f8824dbe97de947cbaac53c44e7f9756a1fba0d37c1eec505"
+source = "git+https://git.pezkuwichain.io/pezkuwichain/core2.git?branch=master#d1abdf18381ccda73916e9a10d9c4075cdb12805"
 dependencies = [
  "memchr",
 ]

Cargo.toml

@@ -1705,3 +1705,6 @@ serde_core = { git = "https://github.com/pezkuwichain/serde.git", branch = "fix-
 # arrayvec 0.7.6 fails on wasm32v1-none: E0223 Self::Target/Self::IntoIter ambiguity
 # (Rust 1.87+ Receiver trait) + missing prelude in char.rs on target_os=none
 arrayvec = { git = "https://git.pezkuwichain.io/pezkuwichain/arrayvec.git", branch = "main" }
+# core2 0.4.0 was yanked from crates.io; wasm sub-builds resolve deps without --locked
+# and fail to select a version. Mirror provides a non-yanked source for resolution.
+core2 = { git = "https://git.pezkuwichain.io/pezkuwichain/core2.git", branch = "master" }