Update plugin creator skill. (#15734)

Add support for home-local plugin + fix policy.

codex-rs/skills/src/assets/samples/plugin-creator/SKILL.md

@@ -26,6 +26,15 @@ python3 .agents/skills/plugin-creator/scripts/create_basic_plugin.py <plugin-nam
 python3 .agents/skills/plugin-creator/scripts/create_basic_plugin.py my-plugin --with-marketplace
 ```
 
+For a home-local plugin, treat `<home>` as the root and use:
+
+```bash
+python3 .agents/skills/plugin-creator/scripts/create_basic_plugin.py my-plugin \
+  --path ~/plugins \
+  --marketplace-path ~/.agents/plugins/marketplace.json \
+  --with-marketplace
+```
+
 4. Generate/adjust optional companion folders as needed:
 
 ```bash
@@ -37,6 +46,7 @@ python3 .agents/skills/plugin-creator/scripts/create_basic_plugin.py my-plugin -
 
 ## What this skill creates
 
+- If the user has not made the plugin location explicit, ask whether they want a repo-local plugin or a home-local plugin before generating marketplace entries.
 - Creates plugin root at `/<parent-plugin-directory>/<plugin-name>/`.
 - Always creates `/<parent-plugin-directory>/<plugin-name>/.codex-plugin/plugin.json`.
 - Fills the manifest with the full schema shape, placeholder values, and the complete `interface` section.
@@ -58,6 +68,8 @@ python3 .agents/skills/plugin-creator/scripts/create_basic_plugin.py my-plugin -
 ## Marketplace workflow
 
 - `marketplace.json` always lives at `<repo-root>/.agents/plugins/marketplace.json`.
+- For a home-local plugin, use the same convention with `<home>` as the root:
+  `~/.agents/plugins/marketplace.json` plus `./plugins/<plugin-name>`.
 - Marketplace root metadata supports top-level `name` plus optional `interface.displayName`.
 - Treat plugin order in `plugins[]` as render order in Codex. Append new entries unless a user explicitly asks to reorder the list.
 - `displayName` belongs inside the marketplace `interface` object, not individual `plugins[]` entries.

codex-rs/skills/src/assets/samples/plugin-creator/references/plugin-json-spec.md

@@ -115,8 +115,10 @@
         "source": "local",
         "path": "./plugins/linear"
       },
-      "installPolicy": "AVAILABLE",
-      "authPolicy": "ON_INSTALL",
+      "policy": {
+        "installation": "AVAILABLE",
+        "authentication": "ON_INSTALL"
+      },
       "category": "Productivity"
     }
   ]
@@ -142,7 +144,9 @@
   - `source` (`string`): Use `local` for this repo workflow.
   - `path` (`string`): Relative plugin path based on the marketplace root.
     - Repo plugin: `./plugins/<plugin-name>`
-    - Local plugin in `~/.agents/plugins/marketplace.json`: `./.codex/plugins/<plugin-name>`
+    - Local plugin in `~/.agents/plugins/marketplace.json`: `./plugins/<plugin-name>`
+  - The same relative path convention is used for both repo-rooted and home-rooted marketplaces.
+    - Example: with `~/.agents/plugins/marketplace.json`, `./plugins/<plugin-name>` resolves to `~/plugins/<plugin-name>`.
 - `policy` (`object`): Marketplace policy block. Always include it.
   - `installation` (`string`): Availability policy.
     - Allowed values: `NOT_AVAILABLE`, `AVAILABLE`, `INSTALLED_BY_DEFAULT`

codex-rs/skills/src/assets/samples/plugin-creator/scripts/create_basic_plugin.py

@@ -191,7 +191,10 @@ def parse_args() -> argparse.Namespace:
     parser.add_argument(
         "--path",
         default=str(DEFAULT_PLUGIN_PARENT),
-        help="Parent directory for plugin creation (defaults to <cwd>/plugins)",
+        help=(
+            "Parent directory for plugin creation (defaults to <cwd>/plugins). "
+            "When using a home-rooted marketplace, use <home>/plugins."
+        ),
     )
     parser.add_argument("--with-skills", action="store_true", help="Create skills/ directory")
     parser.add_argument("--with-hooks", action="store_true", help="Create hooks/ directory")
@@ -202,12 +205,19 @@ def parse_args() -> argparse.Namespace:
     parser.add_argument(
         "--with-marketplace",
         action="store_true",
-        help="Create or update <cwd>/.agents/plugins/marketplace.json",
+        help=(
+            "Create or update <cwd>/.agents/plugins/marketplace.json. "
+            "Marketplace entries always point to ./plugins/<plugin-name> relative to the "
+            "marketplace root."
+        ),
     )
     parser.add_argument(
         "--marketplace-path",
         default=str(DEFAULT_MARKETPLACE_PATH),
-        help="Path to marketplace.json (defaults to <cwd>/.agents/plugins/marketplace.json)",
+        help=(
+            "Path to marketplace.json (defaults to <cwd>/.agents/plugins/marketplace.json). "
+            "For a home-rooted marketplace, use <home>/.agents/plugins/marketplace.json."
+        ),
     )
     parser.add_argument(
         "--install-policy",