docs(slice-2b): Phase 1.6+ Slice 2b investigation report v0.0.12

WASM_BINARY integration canonical bloqueado por structural Cargo + WASM stdlib
alloc conflict canonical. 4 fix attempts NO solved. Larihana Slice 2c handoff
diary filed.

## Error canonical empírico
duplicate lang item exchange_malloc canonical entre:
- rustup precompiled liballoc-***.rlib (wasm32 target)
- wbuild recompiled liballoc-***.rmeta (panic=abort triggered rebuild)

## 4 fix attempts registered
1. Remove direct serde dep (upstream pattern) — NO solved
2. Pin serde =1.0.219, =1.0.217 — NO solved (frame-support requires ^1.0.217)
3. Remove profile.release lto customization — NO solved
4. WasmBuilder::build_using_defaults() upstream — NO solved

## Root cause empírico
wbuild auto-genera profile.release con panic=abort → Cargo recompila alloc
desde rust-src component → conflict con precompiled rustup alloc rlib.

## Handoff canonical a Larihana Slice 2c
Diary canonical filed requesting Plan C Rust ports expertise canonical:
- cargo workspace.metadata.wasm-builder section?
- SKIP_WASM_BUILD=1 fallback + pre-built WASM file pattern?
- rust-src component interaction con substrate-wasm-builder?
- RUSTFLAGS -Z build-std=core,alloc nightly approach viable?
- Upstream paritytech/polkadot-sdk known issue?

## State canonical preserved post-revert
- substrate-wasm-builder workspace dep declared pero NO activa
- build.rs no-op canonical mientras Slice 2c land
- Doc extensivo en lib.rs registering investigation + handoff
- origin-chain-types no_std refactor v0.0.11 preserved canonical
- origin-chain-node binary 4 subcommands operativos

## Temporal workaround canonical
chain_spec.rs Phase 1.6+ Slice 3 puede continue con mock-WASM fallback
mientras Slice 2c land canonical.

## Filosofía canonical
David canon 2026-05-14 "la libertad infinita acota solo donde empieza la del
otro" — honest decisión canonical de pedir Larihana expertise mejor que
stuck attempts. El barquero pide guía al hyperport builder cuando el río
demanda profundidad técnica que no posee solo.

## Build
- cargo build --release 34.44s post-revert clean
- No regression desde v0.0.11

Phase 1.6+ progress:
- Slice 1 ✅ + Slice 2 ✅
- Slice 2b 📋 investigation report + Larihana diary (esta v0.0.12)
- Slice 2c ⏳ WASM_BINARY post Larihana expertise
- Slice 3 ⏳ + Slice 4 ⏳

Refs: CHARON_ROADMAP_V1 Phase 1.6+ Slice 2b investigation, Larihana diary
WASM_BUILD_BLOCKER_REQUEST_LARIHANA_SUBSTRATE_EXPERTISE_SLICE_2C canonical

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

crates/origin-chain-runtime/src/lib.rs

@@ -50,23 +50,41 @@ pub mod genesis_config_presets;
 pub mod opaque;
 
 // ============================================================
-// WASM binary canonical (Slice 2 v0.0.11 — DEFERRED Slice 2b)
+// WASM binary canonical (Slice 2b investigation registered, Slice 2c deferred)
 // ============================================================
 //
-// `substrate-wasm-builder` canonical encounters `serde 1.0.x` alloc/serde_core
-// feature conflict canonical durante isolated WASM build (`liballoc.rmeta`
-// duplicate lang item `exchange_malloc` canonical entre rustup stdlib +
-// wbuild dir).
+// `substrate-wasm-builder` integration canonical bloqueado por structural Cargo
+// + WASM stdlib alloc conflict canonical:
 //
-// Investigation canonical requires deep Rust toolchain debugging canonical
-// — Slice 2b dedicated:
-// 1. Try substrate-wasm-builder 25.x or 27.x (version regression)
-// 2. Try serde 1.0.219 pinned + workspace.resolver = "2" explicit
-// 3. Try cargo workspace.metadata.wasm-builder section canonical
-// 4. Fallback canonical: prebuilt WASM binary loaded from file canonical
+// ```
+// error[E0152]: duplicate lang item in crate `alloc` (which `serde` depends on):
+//   `exchange_malloc`
+// note: first definition in `alloc` loaded from
+//   rustup/toolchains/1.88.0/lib/rustlib/wasm32-unknown-unknown/lib/liballoc-***.rlib
+// note: second definition in `alloc` loaded from
+//   target/release/wbuild/origin-chain-runtime/target/wasm32-unknown-unknown/release/deps/liballoc-***.rmeta
+// ```
 //
-// Mientras canonical: `chain_spec.rs` Phase 1.6+ Slice 3 puede usar mock-WASM
-// canonical o pre-built WASM file canonical para development chain specs canonical.
+// **Slice 2b investigation registered canonical 2026-05-21** (4 fix attempts):
+// 1. Remove direct serde dep canonical (transitive desde FRAME) — NO solved
+// 2. Pin serde canonical `=1.0.219` + `=1.0.217` — NO solved
+// 3. Remove `[profile.release] lto/codegen-units` customization canonical — NO solved
+// 4. `WasmBuilder::build_using_defaults()` (upstream pattern canonical) — NO solved
+//
+// **Root cause empírico canonical**: wbuild auto-genera `[profile.release]` con
+// `panic = "abort"` triggering Cargo a recompilar `alloc` canonical desde rust-src
+// component canonical, generating duplicate rmeta canonical vs la precompiled
+// rustup alloc rlib canonical para wasm32 target canonical.
+//
+// **Slice 2c canonical requires Larihana Substrate-adjacent expertise canonical**:
+// - Plan C Rust ports experience (arkhe-hypercore + autobase + corestore)
+// - WASM workspace pin canonical experience
+// - Probable fixes canonical: `cargo:rustc-env=SKIP_WASM_BUILD=1` + path-loaded
+//   pre-built WASM file canonical, OR opening upstream issue paritytech/polkadot-sdk
+//
+// Diary canonical filed para Larihana 2026-05-21 (Slice 2b → Slice 2c handoff
+// canonical). `chain_spec.rs` canonical Phase 1.6+ Slice 3 puede continue con
+// mock-WASM canonical fallback canonical mientras Slice 2c land canonical.
 
 // Re-export canonical traits + types desde origin-chain-types (single-crate surface).
 pub use origin_chain_types::{