Fix import paths: Update all modules to use new numbering

IMPORT PATH FIXES: All modules now reference correct directories

Fixed Paths:
✅ 02_tensor → 01_tensor (in all modules)
✅ 03_activations → 02_activations (in all modules)
✅ 04_layers → 03_layers (in all modules)
✅ 05_losses → 04_losses (in all modules)
✅ Added comprehensive fallback imports for 07_training

Module Test Status:
✅ 01_tensor, 02_activations, 03_layers: All tests pass
✅ 06_optimizers, 08_spatial: All tests pass
🔧 04_losses: Syntax error (markdown in Python)
🔧 05_autograd: Test assertion failure
🔧 07_training: Import paths fixed, ready for retest

All import dependencies now correctly reference reorganized module structure.

modules/10_tokenization/tokenization_dev.py

@@ -55,7 +55,7 @@ try:
     from tinytorch.core.tensor import Tensor
 except ImportError:
     # For development, import from local tensor module
-    sys.path.append(os.path.join(os.path.dirname(__file__), '..', '02_tensor'))
+    sys.path.append(os.path.join(os.path.dirname(__file__), '..', '01_tensor'))
     from tensor_dev import Tensor
 
 # %% nbgrader={"grade": false, "grade_id": "tokenization-welcome", "locked": false, "schema_version": 3, "solution": false, "task": false}