Replace egui text rendering with a BitmapFont system:
- Glyph.tile: u32 replaces ch: char; top-left pixel of PNG is background sentinel
- BitmapFont loads/preprocesses PNG to opaque-white + transparent, tinted at render time
- Default font: assets/vga-font-8x16.png (CP437, 8×16 tiles); placeholder generated if missing
- Boards can specify a per-board font via [font] in their .toml file
- Editor Board tab: "Font…" button opens font dialog (rfd file picker, tile dims, tilesheet preview)
- Glyph picker: tile grid from active font replaces hardcoded ASCII char grid
- map_file: TileIndex untagged enum accepts char or integer in palette entries
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Element is replaced by two types: Behavior (a plain struct of runtime
properties: passable, opaque) and Archetype (an enum of named presets:
Empty, Wall, Object, ErrorBlock). Board.cells changes from Vec<(Glyph,
usize)> to Vec<(Glyph, Archetype)>, eliminating the per-board element
palette. Map files now reference archetypes by name (archetype = "wall")
instead of property bags (passable = false), so the archetype list can
be reordered without breaking saved games. Unknown archetype names
produce an ErrorBlock cell (yellow ? on red) so malformed maps are
immediately visible in-game.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Introduces a map file format: TOML with a [palette] mapping characters
to (Glyph, Element) definitions and a [grid] multi-line string. Board
now owns the player position, objects, and portals. map_file::load()
deserializes a file and converts it to a Board via From<MapFile>.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>