feat: rename project to TTTK

- Update package name and CLI binary to 'tttk'
- Revise documentation to reflect new name
- Add default serve behavior when no subcommand is given
- Add directory existence check in serve command
- Refactor inline comments to Chinese

package.json

@@ -1,11 +1,10 @@
 {
-  "name": "ttrpg-tools",
+  "name": "tttk",
   "version": "0.0.1",
-  "description": "A tabletop RPG toolbox based on solid.js and rsbuild",
+  "description": "A tabletop RPG toolkit for previewing and compiling TTRPG campaign content",
   "type": "module",
   "bin": {
-    "ttrpg": "./dist/cli/index.js",
-    "ttt": "./dist/cli/index.js"
+    "tttk": "./dist/cli/index.js"
   },
   "main": "./dist/index.js",
   "module": "./dist/index.js",
@@ -22,6 +21,7 @@
     "cli:dev": "tsc -p tsconfig.cli.json --watch",
     "cli:build": "tsc -p tsconfig.cli.json",
     "ttrpg": "node --loader ts-node/esm ./src/cli/index.ts",
+    "tttk": "node --loader ts-node/esm ./src/cli/index.ts",
     "test": "jest",
     "prepare": "npx husky"
   },