docs: add documentation for Deno config provider plugin

docs/plugins/README.md

@@ -28,6 +28,7 @@ marketplace-style index for those plugins and a quick reference for how each one
 | `scoop`      | Command-line Installer Provisioning Framework                           | `config_provider` | [Details](./scoop.md)     |
 | `sdkman`     | Software Development Kit Manager for Java Ecosystem                     | `config_provider` | [Details](./sdkman.md)    |
 | `syncthing`  | Continuous File Synchronization Framework                               | `config_provider` | [Details](./syncthing.md) |
+| `deno`       | JavaScript and TypeScript Runtime Config Provider                       | `config_provider` | [Details](./deno.md)      |
 | `winget`     | Manages Winget CLI `settings.json`, separate from package installation. | `config_provider` | [Details](#winget)        |
 | `7-zip`      | High-Ratio File Archiver and Compression Tool                           | `config_provider` | [Details](./7-zip.md)     |
 

docs/plugins/deno.md

@@ -0,0 +1,84 @@
+# Deno Plugin
+
+## Overview
+
+The Deno plugin manages configuration for the Deno runtime by reading and writing settings to your project's `deno.json` (or `deno.jsonc`) file.
+
+## Prerequisites
+
+- Deno installed
+- Available in PATH
+- Windows 10 or later
+
+## Configuration Schema
+
+| Key | Purpose |
+| --- | ------- |
+| importMap | Path to an import map file |
+| compilerOptions | TypeScript compiler options |
+| lint | Linting configuration |
+| fmt | Code formatting configuration |
+| tasks | Deno task definitions |
+| nodeModulesDir | Whether to use a node_modules directory |
+| unstable | Unstable feature flags |
+| vendor | Vendoring configuration |
+| permissions | Default permissions |
+| publish | Publishing configuration |
+| lock | Lockfile configuration |
+| typeCheckOnRun | Enable type checking on deno run |
+| watch | File watching configuration |
+
+## Usage Examples
+
+### Basic formatter and linter config
+
+```yaml
+extensions:
+  deno:
+    settings:
+      fmt:
+        indentWidth: 2
+        singleQuote: true
+      lint:
+        rules:
+          tags:
+            - recommended
+```
+
+### With import map and task definitions
+
+```yaml
+extensions:
+  deno:
+    settings:
+      importMap: "./import_map.json"
+      tasks:
+        start: "deno run --allow-net main.ts"
+        test: "deno test --allow-read"
+```
+
+### Using node_modules and unstable features
+
+```yaml
+extensions:
+  deno:
+    settings:
+      nodeModulesDir: true
+      unstable:
+        - "bare-node-builtins"
+        - "sloppy-imports"
+```
+
+## Verification Steps
+
+```powershell
+deno --version
+```
+
+## Notes / Caveats
+
+- Only the predefined set of Deno settings listed above are supported; unknown keys are ignored.
+- The plugin automatically backs up your existing `deno.json` before making any changes.
+- If both `deno.json` and `deno.jsonc` exist, `deno.json` takes priority.
+- This plugin only manages `deno.json` settings — it does not install Deno itself.
+- Windows only: this plugin is part of WinHome, a Windows developer environment tool.