Fix Explosion mixin for 1.21.1

docs/agent-handoff.md

@@ -2,7 +2,7 @@
 
 ## Current State
 
-The repository now contains a private NeoForge `21.1.228` / Minecraft `1.21.1` porting scaffold for Explosion Overhaul.
+The repository now contains a private NeoForge `21.1.225` / Minecraft `1.21.1` porting scaffold for Explosion Overhaul.
 
 The Gitea runner has been used for:
 
@@ -22,6 +22,7 @@ The Gitea runner has been used for:
 - Repaired CFR control-flow artifacts in:
   - `AsyncCraterManager`
   - `BlockIndexManager`
+- Updated the `ExplosionMixin` complex constructor injection descriptor for Minecraft `1.21.1` after a client bootstrap crash showed the old Forge `1.20.1` constructor target no longer exists.
 - Fixed runner setup issues:
   - executable `gradlew`
   - tracked `gradle-wrapper.jar`
@@ -32,6 +33,7 @@ The Gitea runner has been used for:
 | Check | Result |
 | --- | --- |
 | `git diff --check` | PASS before last committed source fixes |
+| `git diff --check` | PASS after NeoForge `21.1.225` metadata change and `ExplosionMixin` runtime crash fix |
 | Gitea decompile workflow | PASS |
 | Gitea build workflow | FAIL, now reaches Java API migration errors |
 
@@ -60,6 +62,7 @@ The remaining failures are real Forge-to-NeoForge/API-porting work, not runner s
 2. Migrate packet registration and all packet handlers away from Forge `SimpleChannel` / `NetworkEvent.Context`.
 3. Replace GUI overlay events and config screen registration.
 4. Re-run the Gitea build after each API family rather than attempting all files at once.
+5. Retest the client jar after the `ExplosionMixin` descriptor fix; the next crash, if any, should be a later runtime/API issue rather than the bootstrap constructor mismatch.
 
 ## Risks