Refactor DAP configuration: Remove duplicate keybinding and improve picker formatting

## Task Description

Refactor the DAP (Debug Adapter Protocol) configuration to improve usability and organization.

## Requirements

1. **Remove duplicate keybinding**
- Unbind `da` as it duplicates `dc` (continue) functionality
- Keep only `dc` for the continue command

2. **Format picker to show configuration source**
- When `dc` opens the configuration picker (in non-debugging scenario), format entries to clearly show:
- Source title (e.g., "Global" or "Project")
- Configuration name
- Visual distinction between built-in configs and launch.json configs

3. **Extract inline configurations**
- Move inline DAP configurations from `lua/plugins/dap.lua` to a new file `lua/plugins/dap-launch.lua`
- Keep only the adapter setup and keybindings in the main file
- Export configurations including:
- TypeScript with ts-node (ESM) config
- Chrome debugging config
- Any other inline configurations

## Acceptance Criteria

- [ ] `da` keybinding is removed
- [ ] Configuration picker shows clear source labels
- [ ] All inline configs moved to `dap-launch.lua`
- [ ] Main `dap.lua` file is cleaner and focused on setup
- [ ] No functionality is lost in the refactoring
- [ ] Headless Neovim test confirms keybindings work

## Testing

Test with: `nvim --headless -u NONE -c 'source test.lua'`
Verify picker formatting by running `dc` in a non-debug session