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/INSTALLATION.md

@@ -243,13 +243,13 @@ cd ~ && git clone <repo> .dotfiles && cd .dotfiles && ./install.sh
 ### Verify Installation
 ```bash
 # Check dotfiles status
-dotstatus
+dot sync status
 
 # Check installed packages
-dotpkgs
+dot packages
 
 # Check machine profile
-dotprofile
+dot profile
 ```
 
 ### Test Key Features
@@ -312,7 +312,7 @@ DOTFILES_SKIP_GITHUB=true ./install.sh
 DOTFILES_SKIP_NPM=true ./install.sh
 
 # Install manually later:
-dotinstall
+dot packages install
 ```
 
 #### Shell Not Supported
@@ -337,13 +337,13 @@ cat ~/.dotfiles/.profile.log
 ```bash
 # If installation fails partway through:
 # 1. Check what was installed
-dotpkgs
+dot packages
 
 # 2. Try installing missing packages
 dotcheck
 
 # 3. Or reset and start over
-dotreset --soft
+dot reset --soft
 ./install.sh
 ```
 
@@ -394,7 +394,7 @@ After successful installation:
 1. **Learn the commands**: [Configuration Reference](CONFIGURATION.md)
 2. **Customize settings**: Edit files in `~/.dotfiles/shared/`
 3. **Set up sync**: Configure git credentials for automatic sync
-4. **Explore features**: Try `dotupdatecheck`, `dotprofile`, `dotstatus`
+4. **Explore features**: Try `dot packages check-updates`, `dot profile`, `dot sync status`
 
 ---