Enable essential plugins and clean up configuration structure

- Enable debug, formatting, telescope, treesitter, and tmux-navigator plugins
- Remove duplicate telescope keybinds from init.lua (now handled by custom plugin)
- Fix tmux-navigator plugin syntax with proper config function and descriptions
- Add KEYBIND_ANALYSIS.md to gitignore for local development notes

This activates powerful functionality that was previously commented out:
• Debug adapter protocol with <leader>d* keybinds
• Auto-formatting on save with conform.nvim
• Enhanced telescope with ripgrep integration
• Additional treesitter languages (nix, cmake, python, etc.)
• Seamless tmux pane navigation

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

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

lua/custom/plugins/init.lua

@@ -4,11 +4,11 @@
 -- See the kickstart.nvim README for more information
 return {
   -- { import = 'custom.plugins.completion' },
-  -- { import = 'custom.plugins.debug' },
-  -- { import = 'custom.plugins.formatting' },
+  { import = 'custom.plugins.debug' },
+  { import = 'custom.plugins.formatting' },
   { import = 'custom.plugins.lsp' },
-  -- { import = 'custom.plugins.nvim-tmux-navigator' },
-  -- { import = 'custom.plugins.telescope' },
+  { import = 'custom.plugins.nvim-tmux-navigator' },
+  { import = 'custom.plugins.telescope' },
   -- { import = 'custom.plugins.theme' },
-  -- { import = 'custom.plugins.treesitter' },
+  { import = 'custom.plugins.treesitter' },
 }