README as a small game website in Crookfinger's voice; INSTALL.md, BESTIARY.md, playable standalone file

- README: logo, badges (Rust, WebAssembly, Claude Code, MIT), intro addressed to the master, features with screenshots, the household, how to play, licences and credits
- INSTALL.md: server, PWA, building, tests, savegame service and API, languages, how to refresh generated files
- BESTIARY.md generated from the game's data (tools/make_bestiary.py) with exported sprites and icons (docs/img, test export_doc_images)
- play/DungeonCraft.html: the whole game in one file to download and play offline

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/gfx.rs

@@ -1975,3 +1975,50 @@ impl Gfx {
         }
     }
 }
+
+#[cfg(test)]
+mod doc_images {
+    use super::*;
+
+    // writes a picture scaled up with nearest pixels
+    fn save(img: &Image, src: Rect, scale: u32, path: &str) {
+        let (w, h) = (src.w as u32 * scale, src.h as u32 * scale);
+        let mut out = Image::gen_image_color(w as u16, h as u16, Color::new(0.0, 0.0, 0.0, 0.0));
+        for y in 0..h {
+            for x in 0..w {
+                let p = img.get_pixel(src.x as u32 + x / scale, src.y as u32 + y / scale);
+                out.set_pixel(x, y, p);
+            }
+        }
+        out.export_png(path);
+    }
+
+    // `cargo test --release export_doc_images -- --ignored` refreshes the pictures in docs/img
+    #[test]
+    #[ignore]
+    fn export_doc_images() {
+        std::fs::create_dir_all("docs/img/units").unwrap();
+        std::fs::create_dir_all("docs/img/icons").unwrap();
+        let sprites = gen_sprites();
+        for &k in SPRITE_KINDS.iter() {
+            let id = crate::game::st(k).name.trim_start_matches("unit.");
+            for (lv, tag) in [(1u32, "1"), (5, "5"), (10, "10")] {
+                save(&sprites, Gfx::sprite_cell(k, false, lv), 8, &format!("docs/img/units/{}_{}.png", id, tag));
+            }
+        }
+        let atlas = gen_atlas();
+        for (k, t) in crate::traps::TRAP_KINDS.iter().enumerate() {
+            save(&atlas, Gfx::cell(I_TRAPS + k as u32), 4, &format!("docs/img/icons/{}.png", t.id()));
+        }
+        for (k, s) in crate::spells::SPELLS.iter().enumerate() {
+            save(&atlas, Gfx::cell(I_SPELLS + k as u32), 4, &format!("docs/img/icons/{}.png", s.id()));
+        }
+        for (id, cell) in [("lightning", I_BOLT), ("heal", I_HEAL), ("summon", I_SUMMON), ("arrow", I_ARROW), ("cannon", I_CANNON), ("magic", I_MAGIC), ("rune", I_RUNE)] {
+            save(&atlas, Gfx::cell(cell), 4, &format!("docs/img/icons/{}.png", id));
+        }
+        for (k, id) in crate::game::ROOM_NAMES.iter().enumerate() {
+            let tex = crate::ui::tool_info(crate::ui::Tool::Room(k)).icon;
+            save(&atlas, Gfx::cell(tex), 4, &format!("docs/img/icons/{}.png", id.trim_start_matches("room.")));
+        }
+    }
+}