docs(coding-agent): remove duplicate packages content from extensions.md

Replace 130 lines of duplicate content with link to packages.md

packages/coding-agent/docs/extensions.md

@@ -127,140 +127,7 @@ Additional paths via `settings.json`:
 }
 ```
 
-Use `pi install`, `pi remove`, `pi list`, and `pi update` to manage packages:
-
-```bash
-pi install npm:@foo/bar@1.0.0
-pi install git:github.com/user/repo@v1
-pi install https://github.com/user/repo  # raw URLs work too
-pi remove npm:@foo/bar
-pi list    # show installed packages
-pi update  # update all non-pinned packages
-```
-
-**Package filtering:** By default, packages load all resources (extensions, skills, prompts, themes). To selectively load only certain resources:
-
-```json
-{
-  "packages": [
-    "npm:simple-pkg",
-    {
-      "source": "npm:shitty-extensions",
-      "extensions": ["extensions/oracle.ts", "extensions/memory-mode.ts"],
-      "skills": ["skills/a-nach-b"],
-      "themes": [],
-      "prompts": []
-    }
-  ]
-}
-```
-
-- Omit a key to load all of that type from the package
-- Use empty array `[]` to load none of that type
-- Paths are relative to package root
-- Use `!pattern` to exclude (e.g., `"themes": ["!funky.json"]`)
-- Glob patterns supported via minimatch (e.g., `"extensions": ["**/*.ts", "!**/deprecated/*"]`)
-- **Layered filtering:** User filters apply on top of manifest filters. If a manifest excludes 10 extensions and user adds one more exclusion, all 11 are excluded.
-
-**Package deduplication:** If the same package appears in both global (`~/.pi/agent/settings.json`) and project (`.pi/settings.json`) settings, the project version wins and the global one is ignored. This prevents duplicate resource collisions when you have the same package installed at both scopes. Package identity is determined by:
-- **npm packages:** Package name (e.g., `npm:foo` and `npm:foo@1.0.0` are the same identity)
-- **git packages:** Repository URL without ref (e.g., `git:github.com/user/repo` and `git:github.com/user/repo@v1` are the same identity)
-- **local paths:** Resolved absolute path
-
-**Discovery rules:**
-
-1. **Direct files:** `extensions/*.ts` or `*.js` → loaded directly
-2. **Subdirectory with index:** `extensions/myext/index.ts` → loaded as single extension
-3. **Subdirectory with package.json:** `extensions/myext/package.json` with `"pi"` field → loads declared paths
-
-```
-~/.pi/agent/extensions/
-├── simple.ts                      # Direct file (auto-discovered)
-├── my-tool/
-│   └── index.ts                   # Subdirectory with index (auto-discovered)
-└── my-extension-pack/
-    ├── package.json               # Declares multiple extensions
-    ├── node_modules/              # Dependencies installed here
-    └── src/
-        ├── safety-gates.ts        # First extension
-        └── custom-tools.ts        # Second extension
-```
-
-```json
-// my-extension-pack/package.json
-{
-  "name": "my-extension-pack",
-  "dependencies": {
-    "zod": "^3.0.0"
-  },
-  "pi": {
-    "extensions": ["./src/safety-gates.ts", "./src/custom-tools.ts"],
-    "skills": ["./skills/"],
-    "prompts": ["./prompts/"],
-    "themes": ["./themes/dark.json"]
-  }
-}
-```
-
-The pi manifest supports glob patterns and exclusions:
-
-```json
-{
-  "pi": {
-    "extensions": ["./extensions", "!**/deprecated/*"],
-    "skills": ["./skills", "!**/experimental/*"],
-    "themes": ["./themes/*.json"]
-  }
-}
-```
-
-**Bundling other pi packages:**
-
-To include resources from another pi package, add it as a dependency with `bundledDependencies` to ensure it's embedded in your published tarball:
-
-```json
-{
-  "name": "my-extension-pack",
-  "dependencies": {
-    "other-pi-package": "^1.0.0"
-  },
-  "bundledDependencies": [
-    "other-pi-package"
-  ],
-  "pi": {
-    "extensions": [
-      "./extensions",
-      "./node_modules/other-pi-package/extensions",
-      "!**/unwanted-extension.ts"
-    ],
-    "skills": [
-      "./skills",
-      "./node_modules/other-pi-package/skills"
-    ]
-  }
-}
-```
-
-`bundledDependencies` embeds the package inside your tarball, preserving the `node_modules/` structure. Without it, npm's hoisting could move the dependency elsewhere, breaking the paths.
-
-**Discoverability:** Add the `pi-package` keyword to your `package.json` so users can find your package on npm:
-
-```json
-{
-  "name": "my-extension-pack",
-  "keywords": ["pi-package", "pi-extension", "..."],
-  ...
-}
-```
-
-Search for pi packages: `curl -s "https://registry.npmjs.org/-/v1/search?text=keywords:pi-package"`
-
-The `package.json` approach enables:
-- Multiple extensions from one package
-- Skills, prompts, and themes declared alongside extensions
-- Third-party npm dependencies (resolved via jiti)
-- Nested source structure (no depth limit within the package)
-- Deployment to and installation from npm
+To share extensions via npm or git, see [packages.md](packages.md).
 
 ## Available Imports