Prepare Minecraft 26.3 technical alpha 1.0.1.2-alpha.1

docs/MINECRAFT_26_3_PORT.md

@@ -365,6 +365,15 @@ The player confirmed the `0.0.0.7-port-dev` bound Linking Book click/travel
 path passes in game on 2026-10-27. The 26.3 target remains incomplete and is
 not ready for a public release or closure of the parent port issue.
 
+### Explicit technical alpha exception
+
+At the player's request, `1.0.1.2-alpha.1` packages this limited 26.3 port as
+an experimental alpha. It is **not** the full mod and does not pass the stable
+release gate above. The alpha label and release notes must state that Ages use
+prototype vanilla terrain, normal authoring and most content are absent, and
+worlds should be disposable or backed up. The 1.21.1 stable release remains
+independent; issues #96–#104 stay open until the full port and validation pass.
+
 ## Verification of this first slice
 
 The 1.21.1 `compileJava` and `build` tasks passed offline after the backend