feat: comprehensive nvim-tree file explorer support

Significantly enhanced nvim-tree integration with complete highlight group
coverage for a polished file explorer experience matching JetBrains IDEs.

Added highlight groups (50+ total):
- UI elements: NormalNC, WinSeparator, CursorLine, StatusLine variants
- Folder types: Symlink folders, empty folders, opened folders
- File types: Exec, Special, Image, Symlink, Modified, Opened, Hidden
- Git status: All states (Dirty, Staged, New, Renamed, Deleted, Merge, Ignored)
- Git decorations: Separate file and folder-level git highlighting
- Clipboard: Cut and Copied item highlights
- Bookmarks: Bookmark highlighting
- LSP Diagnostics: Error, Warning, Information, Hint
- Window Picker: Visual selection for window targeting
- Live Filter: Search prefix and value highlighting
- Indent Markers: Tree structure visualization

Color mapping follows JetBrains Darcula conventions:
- Git added/staged: Green (#499C54)
- Git modified/dirty: Yellow/Warning (#BE9117)
- Git deleted: Red/Error (#BC3F3C)
- Executable files: Bold green
- Special files (README, Makefile): Underlined yellow
- Symlinks: Italic blue
- Hidden/ignored: Dimmed gray

This provides the most comprehensive nvim-tree theming with proper
visual hierarchy and JetBrains-style git integration.

lua/lush_theme/darcula-solid.lua

@@ -473,20 +473,81 @@ return lush(function()
 		LspCodeLensSeparator({ fg = p.gray }),
 
 		-- == Plugin Support == --
-		-- NvimTree
+		-- NvimTree (Enhanced File Explorer)
 		NvimTreeNormal({ bg = p.bg, fg = p.fg }),
+		NvimTreeNormalNC({ bg = p.bg, fg = p.fg }),
 		NvimTreeVertSplit({ fg = p.border_dark, bg = p.bg }),
+		NvimTreeWinSeparator({ fg = p.border_dark, bg = p.bg }),
 		NvimTreeEndOfBuffer({ fg = p.bg }),
+		NvimTreeCursorLine({ bg = p.bg_current_line }),
+		NvimTreeCursorColumn({ bg = p.bg_current_line }),
+		NvimTreeStatusLine({ bg = p.bg_light, fg = p.fg }),
+		NvimTreeStatusLineNC({ bg = p.bg_light, fg = p.fg_dark }),
+
+		-- Folders
 		NvimTreeFolderIcon({ fg = p.number }),
 		NvimTreeFolderName({ fg = p.fg }),
 		NvimTreeOpenedFolderName({ fg = p.number, gui = "bold" }),
 		NvimTreeEmptyFolderName({ fg = p.fg_dark }),
+		NvimTreeSymlinkFolderName({ fg = p.blue, gui = "italic" }),
+
+		-- Files
 		NvimTreeRootFolder({ fg = p.keyword, gui = "bold" }),
+		NvimTreeExecFile({ fg = p.hint, gui = "bold" }),
 		NvimTreeSpecialFile({ fg = p.function_call, gui = "underline" }),
+		NvimTreeImageFile({ fg = p.constant }),
+		NvimTreeSymlink({ fg = p.blue, gui = "italic" }),
+		NvimTreeModifiedFile({ fg = p.warning }),
+		NvimTreeOpenedFile({ fg = p.number, gui = "bold" }),
+		NvimTreeHiddenFile({ fg = p.fg_dark }),
+
+		-- Git Status
 		NvimTreeGitDirty({ fg = p.warning }),
 		NvimTreeGitStaged({ fg = p.hint }),
 		NvimTreeGitNew({ fg = p.hint }),
+		NvimTreeGitRenamed({ fg = p.number }),
 		NvimTreeGitDeleted({ fg = p.error }),
+		NvimTreeGitMerge({ fg = p.constant }),
+		NvimTreeGitIgnored({ fg = p.fg_dark }),
+
+		-- File Highlights (decorations)
+		NvimTreeFileDirty({ fg = p.warning }),
+		NvimTreeFileStaged({ fg = p.hint }),
+		NvimTreeFileNew({ fg = p.hint }),
+		NvimTreeFileRenamed({ fg = p.number }),
+		NvimTreeFileDeleted({ fg = p.error }),
+		NvimTreeFileMerge({ fg = p.constant }),
+		NvimTreeFileIgnored({ fg = p.fg_dark }),
+
+		-- Folder Highlights (decorations)
+		NvimTreeFolderDirty({ fg = p.warning }),
+		NvimTreeFolderStaged({ fg = p.hint }),
+		NvimTreeFolderNew({ fg = p.hint }),
+		NvimTreeFolderRenamed({ fg = p.number }),
+		NvimTreeFolderDeleted({ fg = p.error }),
+		NvimTreeFolderMerge({ fg = p.constant }),
+		NvimTreeFolderIgnored({ fg = p.fg_dark }),
+
+		-- Clipboard
+		NvimTreeCutHL({ fg = p.error, gui = "bold" }),
+		NvimTreeCopiedHL({ fg = p.hint, gui = "bold" }),
+
+		-- Bookmarks
+		NvimTreeBookmarkHL({ fg = p.constant, gui = "bold" }),
+
+		-- Diagnostics
+		NvimTreeLspDiagnosticsError({ fg = p.error }),
+		NvimTreeLspDiagnosticsWarning({ fg = p.warning }),
+		NvimTreeLspDiagnosticsInformation({ fg = p.info }),
+		NvimTreeLspDiagnosticsHint({ fg = p.hint }),
+
+		-- Window Picker
+		NvimTreeWindowPicker({ bg = p.bg_visual, fg = p.function_call, gui = "bold" }),
+
+		-- Indent Markers
+		NvimTreeIndentMarker({ fg = p.bg_darker }),
+		NvimTreeLiveFilterPrefix({ fg = p.keyword, gui = "bold" }),
+		NvimTreeLiveFilterValue({ fg = p.function_call, gui = "bold" }),
 
 		-- Telescope
 		TelescopeNormal({ bg = p.bg_light, fg = p.fg }),