docs: update all documentation for new dot command interface

Replace all legacy command references with new unified `dot` syntax
throughout documentation. Remove backward compatibility sections and
streamline examples to use modern command structure.

Changes:
- README.md: Update command interface section with new syntax
- INSTALLATION.md: Replace legacy commands in examples
- ONE_LINE_INSTALL.md: Update verification commands

All examples now use intuitive `dot <action>` format instead of
fragmented `dotcommand` aliases.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

docs/ONE_LINE_INSTALL.md

@@ -69,13 +69,13 @@ curl -fsSL https://raw.githubusercontent.com/your-username/dotfiles/main/install
 ### Verify Everything Works
 ```bash
 # Check system status
-dotstatus
+dot sync status
 
 # Check your profile
-dotprofile
+dot profile
 
 # Check installed packages
-dotpkgs
+dot packages
 
 # Try some shortcuts
 l              # Enhanced file listing