Significantly improves the stability, performance, and visual quality of the ncurses renderer.
**Renderer Improvements (`clay_renderer_ncurses.c`):**
* **Flicker Reduction**:
* Removed `erase()` call at the start of the frame to enable differential rendering.
* Implemented "Dirty Check" optimizations for Rectangles, Borders, and Text. The renderer now reads the existing screen content (using `mvinch`, `mvin_wch`, `mvin_wchnstr`) and only issues draw commands if the content or color differs.
* Hardened Rectangle dirty check to mask out volatile attributes (comparing only `A_CHARTEXT | A_COLOR`), preventing false-positive redraws caused by internal terminal flags.
* **Memory Safety**:
* Fixed internal ncurses memory leaks by calling `delscreen(set_term(NULL))` in `Clay_Ncurses_Terminate` to properly free the default screen wrapper.
* **Visual Features**:
* Added support for **Rounded Corners**: Borders with `cornerRadius > 0` now render using Unicode arc characters (`╭`, `╮`, `╯`, `╰`).
* Upgraded standard borders to use full Unicode box-drawing characters.
**Example Application Updates (`ncurses-example/main.c`):**
* **Layout Stability**:
* Refactored all layout dimensions and gaps to use `CLAY_NCURSES_CELL_WIDTH` (8) and `CLAY_NCURSES_CELL_HEIGHT` (16) macros, ensuring strict grid alignment.
* Fixed vertical jitter in "Profile Icon" and text headers by enforcing exact height multiples and top-alignment, eliminating sub-pixel rounding errors during scroll.
* **New UI Elements**:
* Added a **Floating Help Modal** (toggled via 'H') to demonstrate Z-ordering and localized input handling.
* Added "Server Status" progress bars to the Sidebar to demonstrate percent-based sizing and colored rectangles.
* Added "Mixed Border" examples to the Sidebar to showcase the new rounded corner capabilities.
* Added "Black" background constant usage for cleaner code.
Significantly enhances the Ncurses renderer capabilities and updates the example application.
Renderer Changes:
- Unicode Support:
- Implemented automatic UTF-8 locale detection and initialization.
- Switched to wide-character handling (`wchar_t`, `mvaddnwstr`) for correct rendering of multi-byte characters (e.g., Emojis).
- Used `wcwidth` for accurate string width measurement.
- Color Support:
- Upgraded from 3-bit (8 colors) to 256-color support (xterm-256color).
- Added `Clay_Ncurses_MatchColor` to map arbitrary RGB values to the nearest color in the standard 6x6x6 color cube.
- Added capability detection to fallback gracefully on simpler terminals.
- Visual Fidelity:
- Implemented background color inheritance (`Clay_Ncurses_GetBackgroundAt`) to simulate transparency.
- Text and borders now render on top of existing background colors instead of resetting to the terminal default.
- Build & POSIX:
- Added `_XOPEN_SOURCE_EXTENDED` and `_XOPEN_SOURCE=700` definitions for standard compliance.
Example Application (clay-ncurses-example):
- Theme:
- Updated to a modern dark theme (Uniform `{20, 20, 20}` background).
- Switched to saturated/bright foreground colors for better contrast.
- Fixes:
- Replaced obsolete `usleep` with POSIX-compliant `nanosleep`.
- Build:
- Updated CMakeLists.txt to enforce linking against `ncursesw` (wide version).
Verified with `clay-ncurses-example` on Linux (xterm-256color).
- **Renderer**: Implemented `clay_renderer_ncurses.c` supporting rectangles, text, borders, and clipping using standard ncurses plotting.
- **Example**: Added `examples/ncurses-example` demonstrating a scrollable "Social Feed" UI with keyboard navigation.
- **Build**: Added `CLAY_INCLUDE_NCURSES_EXAMPLES` option to root `CMakeLists.txt` and integrated the new example.
- **CompConfig**: Updated `.gitignore` to strictly exclude `build/`, `_deps/`, and other standard CMake artifacts.
