feat: Add Treesitter support, marks caching, and fixed-size UI

Add marks file caching in storage module that validates against file modification times to reduce I/O operations.
Implement comprehensive Treesitter integration for more accurate context detection when generating mark names, with fallback to regex patterns.
Redesign the UI with a fixed 80x20 window size, featuring dimmed help text at the bottom and visual separators between sections.

The changes maintain backward compatibility while providing significant performance gains through caching and more intelligent mark naming through Treesitter AST analysis.

Author: alexekdahl

README.md

@@ -18,12 +18,12 @@ Vim's built-in marks are great, but they're global and get messy fast. Marksman
 
 - **Project-scoped marks** - Each project gets its own isolated set of bookmarks
 - **Persistent storage** - Your marks survive Neovim restarts with automatic backup
-- **Smart naming** - Context-aware auto-generation based on code structure
+- **Smart naming** - Context-aware auto-generation using Treesitter and pattern matching
 - **Quick access** - Jump to marks with single keys or interactive UI
 - **Enhanced search** - Find marks by name, file path, or content with real-time filtering
 - **Mark reordering** - Move marks up/down to organize them as needed
 - **Multiple integrations** - Works with Telescope, Snacks.nvim, and more
-- **Memory efficient** - Lazy loading, cleanup, and debounced operations
+- **Memory efficient** - Lazy loading, marks caching, cleanup, and debounced operations
 - **Robust error handling** - Graceful fallbacks and comprehensive validation
 
 ## Requirements
@@ -135,6 +135,9 @@ require("marksman").setup({
     ProjectMarksFile = { fg = "#56B6C2" },
     ProjectMarksLine = { fg = "#D19A66" },
     ProjectMarksText = { fg = "#5C6370", italic = true },
+    ProjectMarksHelp = { fg = "#5C6370" },
+    ProjectMarksBorder = { fg = "#5A5F8C" },
+    ProjectMarksSeparator = { fg = "#3E4451" },
   },
 })
 ```
@@ -253,15 +256,19 @@ marksman.show_marks("optional_search")
 
 ## How it works
 
-**Storage**: Marks are stored in `~/.local/share/nvim/marksman_[hash].json` per project with automatic backup.
+**Storage**: Marks are stored in `~/.local/share/nvim/marksman_[hash].json` per project with automatic backup and caching for improved performance.
 
-**Smart Naming**: Auto-generates context-aware names:
+**Smart Naming**: Auto-generates context-aware names using Treesitter when available, falling back to pattern matching:
 - `fn:calculate_total` for functions
 - `class:UserModel` for classes  
 - `var:api_key` for variables
+- `method:process_data` for methods
+- `interface:Serializable` for interfaces
+- `trait:Iterator` for Rust traits
+- `type:Config` for type definitions
 - `filename:line` as fallback
 
-**Project Detection**: Uses Git root, common project files (.git, package.json, etc.), or current directory.
+**Project Detection**: Uses Git root, common project files (.git, package.json, etc.), or current directory with 30-second caching.
 
 **Search**: Multi-field search across mark names, file paths, and code content.