Fix fuel implementation in PHP

AGENTS.md

@@ -2,7 +2,7 @@
 
 > For AI agents and contributors working in this repository.
 
-## 0. TDD
+## 0. Test Driven Development
 
 Write and discuss tests with the user before implementing any implementation code.
 
@@ -178,27 +178,7 @@ tricu/
 └── AGENTS.md           # This file
 ```
 
-## 9. JS Arboricx Runtime
-
-A JavaScript implementation of the Arboricx portable bundle runtime lives in `ext/js/`.
-It is a reference implementation — not a tricu source parser. It reads `.arboricx` files produced by the Haskell toolchain, verifies Merkle node hashes, reconstructs tree values, and reduces them.
-
-From project root:
-```bash
-node ext/js/src/cli.js inspect test/fixtures/id.arboricx
-node ext/js/src/cli.js run test/fixtures/true.arboricx
-```
-
-The JS runtime implements:
-- Bundle binary format parsing (header, section directory, manifest, nodes)
-- SHA-256 Merkle node hash verification against canonical payloads
-- Closure verification (all child references present)
-- Tree reconstruction from node DAG
-- Core `apply` reduction rules
-- Basic codecs (decodeResult)
-- CLI: `inspect` and `run` commands
-
-## 10. Content Store Workflow (Custom DB)
+## 9. Content Store Workflow (Custom DB)
 
 The content store location is controlled by the `TRICU_DB_PATH` environment variable. When set, `eval` mode automatically loads all stored terms into the initial environment, so you can call any previously imported/evaluated term by name.
 
@@ -226,14 +206,14 @@ t> !definitions
 
 Without `TRICU_DB_PATH` set, `eval` uses only the terms defined in the input file(s).
 
-## 11. Development Tips
+## 10. Development Tips
 
 - **REPL:** `nix run .#` starts the interactive tricu REPL.
 - **Evaluate files:** `nix run .# -- eval -f demos/equality.tri`
 - **GHC options:** `-threaded -rtsopts -with-rtsopts=-N` for parallel runtime. Use `-N` RTS flag for multi-core.
 - **Upx** is in the devShell for binary compression if needed.
 
-## 12. Viewing Haskell Dependency Docs from Nix
+## 11. Viewing Haskell Dependency Docs from Nix
 
 When you need Haddock documentation for a Haskell dependency available in Nixpkgs, build the package's `doc` output directly with `^doc`.