cleanup: QOL improvements — gitignore, Tags constants, remove debug artifacts

- Add .DS_Store, unused/, .vscode/settings.json to .gitignore
- Add .editorconfig (tabs for Lua, LF, UTF-8)
- Fix duplicate submodule entry in .gitmodules
- Add Tags table (player, tank, ground, granade, ammoCrate) — replace magic numbers
- Add SCREEN_W/SCREEN_H constants
- Fix leaked global variable `c` in Game.lua
- Remove Noble.showFPS = true from BomberScene
- Remove debug print() calls from granade, enemy, BomberScene
- Fix clean_build_dir glob bug in both build scripts
- Make PLAYDATE_SDK_PATH configurable via env var

source/main.lua

@@ -36,6 +36,17 @@ CollideGroups = {
     granade = 6
 }
 
+Tags = {
+    player = 1,
+    tank = 2,
+    ground = 3,
+    granade = 154,
+    ammoCrate = 155,
+}
+
+SCREEN_W = 400
+SCREEN_H = 240
+
 Maps = {
     {
         id = 1,