Update project docs and metadata for new layout

Document the host/container split and update the package scripts and ignore rules to match the reorganized structure.

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-opencode)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

package.json

@@ -5,10 +5,10 @@
   "type": "module",
   "description": "Reuse host Git HTTPS credentials inside Docker containers on macOS.",
   "scripts": {
-    "start": "./start.sh",
-    "stop": "./stop.sh",
-    "status": "./status.sh",
-    "check": "bash -n start.sh && bash -n stop.sh && bash -n status.sh && bash -n configure-container.sh && bash -n git-credential-hostproxy && node --check server.mjs && node --check helper.mjs"
+    "start": "./host/start.sh",
+    "stop": "./host/stop.sh",
+    "status": "./host/status.sh",
+    "check": "bash -n host/start.sh && bash -n host/stop.sh && bash -n host/status.sh && bash -n container/configure-git.sh && bash -n container/git-credential-hostproxy && node --check host/server.mjs && node --check container/helper.mjs"
   },
   "engines": {
     "node": ">=18"