Add Power Grid NeoForge port submodule

.codex/project.md

@@ -4,7 +4,10 @@
 
 `minecraft-renew-mod` is a local workspace for Minecraft mod porting and prototyping.
 
-The active project is `create-limited-draining/`, a NeoForge port of Create: Limited Draining for Minecraft 1.21.1 and Create 6.0.10.
+The active projects are:
+
+- `create-limited-draining/`, a NeoForge port of Create: Limited Draining for Minecraft 1.21.1 and Create 6.0.10.
+- `power-grid/`, the official Create: Power Grid `architectury-1.21.1/dev` upstream branch tracked as a submodule for NeoForge 1.21.1 verification.
 
 Repository:
 
@@ -33,6 +36,13 @@ From `create-limited-draining/`:
 .\gradlew dependencies --configuration runtimeClasspath
 ```
 
+From `power-grid/`:
+
+```powershell
+.\gradlew :forge:compileJava -x :native:buildWindows -x :native:buildLinux --no-daemon
+.\gradlew :forge:remapJar -x :native:buildWindows -x :native:buildLinux --no-daemon
+```
+
 Command notes:
 
 - Build: `.\gradlew build`
@@ -40,6 +50,7 @@ Command notes:
 - Lint: no separate lint command is currently documented
 - Audit/dependency review: `.\gradlew dependencies --configuration runtimeClasspath`
 - README generation: README is maintained manually; no blueprint generator is configured
+- Power Grid NeoForge artifact build: `.\gradlew :forge:remapJar -x :native:buildWindows -x :native:buildLinux --no-daemon`
 
 ## Stack
 
@@ -59,12 +70,14 @@ Release artifacts are produced in:
 
 ```text
 create-limited-draining/build/libs/
+power-grid/forge/build/libs/
 ```
 
 Expected files:
 
 ```text
 createlimiteddraining-*.jar
+powergrid-*.jar
 ```
 
 ## Security Rules