Move do_render from internal procedure to module procedure in new
render_state_mod. This avoids gfortran trampolines that required
executable stack for callbacks.

- Remove -Wl,-z,noexecstack flag which crashes gfortran trampolines
- Add -fno-trampolines compiler flag (best practice)
- Fix unused argument suppression using c_associated() instead of transfer()
- gfortran requires executable stack for internal procedure callbacks (do_render)

- Remove unused parameter from dispatch_dec_private()
- Remove unused variable in dispatch_sgr()
- Add dummy references for unused GLFW callback arguments
- Mark selection_contains and selection_normalize as pure functions
- Add -Wl,-z,noexecstack linker flag to fix executable stack warning

- Skip rendering when window loses focus to prevent glfwSwapBuffers
  from blocking on Wayland frame callbacks
- Add glfwGetWindowAttrib binding and window_is_focused() function
- Track focus state to ensure initial render and clean unfocus state

- Replace glfwPollEvents with glfwWaitEventsTimeout for proper Wayland
  ping-pong handling when window is on inactive workspace
- Add desktop entry file for application launchers (wofi, rofi, etc.)
- Reduces CPU usage when terminal is idle

Implements two major features for the terminal:

Tabs:
- Cmd+T to create new tab
- Cmd+W to close tab (context-aware: closes pane first if multiple)
- Cmd+[/] to switch between tabs
- Cmd+1-9 to jump to specific tab
- Dynamic tab bar that hides when only one tab exists
- Each tab maintains independent shell state

Split Panes:
- Cmd+\ to split vertically (side-by-side panes)
- Cmd+Shift+\ to split horizontally (stacked panes)
- Cmd+Arrow keys for directional pane navigation
- Cmd+H/J/K/L for vim-style pane navigation
- Each pane has its own independent PTY/shell
- Inactive panes are visually dimmed (60% brightness)
- Scissor-based viewport clipping for each pane
- Splits default to 50% of current pane's space

Architecture:
- New pane_mod module for pane data structure
- New layout_mod for split calculations and navigation
- Refactored tab_manager to contain panes array per tab
- Added glScissor binding for pane viewport clipping

Implement real-time font size changes via keyboard shortcuts:
- Ctrl/Cmd + = (or +): Increase font size by 2px
- Ctrl/Cmd + -: Decrease font size by 2px
- Ctrl/Cmd + 0: Reset to config default

Font size is clamped to 8-72px range. Terminal dimensions
automatically recalculate and PTY is resized accordingly.
Fallback font path is saved at startup and reloaded on size
change to preserve Unicode glyphs (fish chevron, icons, etc).

Add TOML parsing for [cursor] section:
- style: "block", "underline", or "bar"/"beam"
- blink: true/false

Apply config values to terminal cursor on startup.

Add cursor_style (block/underline/bar) and cursor_blink fields to
config_t with sensible defaults. TOML parsing not yet implemented.

Use ascender (not cell_height) for baseline positioning. Text baseline
is now at y + ascender, leaving room below for descenders. Cursor
rendering updated to align properly with text glyphs.

Store fallback font's ascender and adjust bearing_y when rendering
glyphs from fallback font. This compensates for different font metrics
between primary and fallback fonts, keeping all glyphs on the same
baseline.

Add pending_wrap flag for deferred line wrapping - cursor stays at EOL
until next character is written, then wraps. This matches xterm behavior
and fixes the ZSH PROMPT_EOL_MARK (%) appearing incorrectly.

Also update DA1/DA2 responses to identify as VT220 with ANSI color support.

The parser was removing quotes before handling inline comments,
causing "#FFFFFF" to become "#FFFFFF" which was then truncated
at the "#" as if it were a comment. Now calls remove_inline_comment
first, which correctly preserves "#" inside quoted strings.

Window appearance can now be configured via TOML:
- [window] opacity = 0.95  (0.0-1.0, default 1.0)
- [window] blur = true     (macOS only, currently stubbed)

Implementation:
- Add toml_get_real() for float parsing in TOML
- Add window_opacity and window_blur to config_t
- Enable GLFW_TRANSPARENT_FRAMEBUFFER when opacity < 1.0
- Use opacity value in glClearColor alpha channel
- Add window_set_blur() function (stub - needs Cocoa integration)

Note: macOS blur requires Cocoa framework which has CMake integration
issues with Fortran compilers. The blur function is stubbed for now.

- Draw selection background for all cells including spaces, not just
  text characters, so selections appear continuous
- Add macOS font paths for fallback fonts (Apple Symbols, Library/Fonts)
- Prioritize finding fonts with common Unicode symbols (❯ chevron)
  before icon-only fonts

Use face->size->metrics.max_advance (scaled 26.6 pixels) instead of
face->max_advance_width (unscaled font units). This was causing
double-width characters and cursor on macOS.

Load configuration at startup from ~/.config/fortty/fortty.toml:
- Apply color palette and default colors to cell module
- Use window dimensions from config
- Pass font path and size to renderer
- Use font metrics for cell dimensions instead of hardcoded values

Add config modules to CMakeLists.txt build.
Includes response handling in main loop for DA1/DSR replies.

Define config_t type with settings for:
- Window: width, height
- Font: path, fallback, size
- Colors: foreground, background, cursor, 16-color palette
- Terminal: scrollback lines
- Shell: program path

Implements config_load with XDG Base Directory support,
hex color parsing (#RRGGBB), and sensible defaults.

Simple TOML parser for fortty configuration files:
- Section parsing: [section]
- Key-value pairs: key = value
- String values with quote handling
- Integer and logical value parsing
- Comment and inline comment support

Provides toml_open, toml_get_string, toml_get_integer,
toml_get_logical for reading configuration values.

Add custom 16-color palette support:
- set_palette_color: override individual palette entries
- set_default_colors: set default foreground/background
- init_default_palette: initialize with VGA-style defaults

Modify color_from_index to use custom palette for indices 0-15,
allowing configuration-driven terminal theming.