Migrate all project files from repo root into prj/<name>/

Moved all 40 existing projects' .prj/.dat files (Layer weights, training
batches, legacy .weights.dat/.test.dat artifacts) from the flat repo root
into their own prj/<name>/ folder via git mv, matching the new path
convention from the previous commit. Filenames are unchanged, only the
directory. Non-project files at root (CLAUDE.md, Makefile, batch/moby
text corpora, the stray Layer.0.training.mat) were left in place.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_016K8Gu7Qejd11JbdiHZqYAs

prj/test/test.Layer.2.weights.dat

@@ -0,0 +1,11 @@
+4 1 2
+0.670845
+-0.811619
+-5.711279
+-4.175210
+-7.722052
+-5.535058
+4.089306 -4.005000 
+1.926863 -0.390126 
+1.514860 8.437363 
+7.283318 4.790333