docs(slice-2d): findings consolidados — serde/std leak via types/std identified

Slice 2d empirical investigation completada (sesión 2 cont 2026-05-24):
- WASM_BUILD_STD=0 resuelve alloc/exchange_malloc (Slice 2c attempt #5)
- NEW layer: panic_impl duplicate via serde/std leak transitive
- Diagnostic vía cargo tree wasm32 -e features: ruta exacta identificada
  `origin-chain-types feature "std"` → `serde feature "std"` activation
- Root cause: dep transitive activa types/std en wasm32 build incluso
  con --no-default-features (probable macro expansion automation)

Slice 2e future requires architectural fix:
- [patch.crates-io] serde override con strict no-std
- O sp-io feature gate adjust
- O wait stable2512-4+ upstream

Mientras Slice 2e land: build.rs no-op + Slice 3 v0.0.13 mock-WASM estable.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

crates/origin-chain-runtime/Cargo.toml

@@ -64,17 +64,10 @@ log.workspace = true
 serde_json.workspace = true
 
 [build-dependencies]
-# Slice 2c canonical multi-attempt findings registered (build.rs doc canonical):
-#   1-4 (Slice 2b 2026-05-21): direct serde / pin / profile / build_using_defaults
-#      — ALL NO solved alloc/exchange_malloc conflict canonical
-#   5 (Slice 2c attempt #5 2026-05-24 sesión 2 cont): WASM_BUILD_STD=0 explicit
-#      → alloc issue RESUELTO canonical. NEW canonical layer canonical surface:
-#      panic_impl duplicate canonical via serde/std leakage canonical.
-#
-# Slice 2d canonical future requires deeper canonical: inverted feature tree
-# identify exact dep canonical activating serde/std + override canonical OR
-# stable2512-4+ upstream fix canonical. Mientras canonical Slice 3 v0.0.13
-# mock-WASM canonical path canonical estable canonical.
+# Slice 2c+2d findings registered (build.rs doc): WASM_BUILD_STD=0 resuelve
+# alloc/exchange_malloc pero descubre serde/std leak via types/std transitive
+# activation. Slice 2e future: [patch.crates-io] serde override o sp-io gate
+# adjust o stable2512-4+ upstream fix. Mientras tanto: no-op + Slice 3 mock-WASM.
 # substrate-wasm-builder = { workspace = true, optional = true }
 
 [features]