Add dotnet-install skill

.claude-plugin/marketplace.json

@@ -8,7 +8,7 @@
       "name": "dotnet-skills",
       "source": "./",
       "description": ".NET skills for coding assistants",
-      "version": "0.7.2"
+      "version": "0.7.3"
     }
   ]
 }

.claude-plugin/plugin.json

@@ -1,7 +1,7 @@
 {
   "name": "dotnet-skills",
   "description": ".NET skills for coding assistants",
-  "version": "0.7.2",
+  "version": "0.7.3",
   "author": {
     "name": "Rich"
   },

skills/dotnet-install/SKILL.md

@@ -0,0 +1,131 @@
+---
+name: dotnet-install
+description: >
+  Install .NET executables to PATH — like cargo install and go install.
+  Use when the user wants to install, manage, or run .NET tools.
+  Covers NuGet packages, GitHub repos, and local projects.
+---
+
+# dotnet-install
+
+## When to Use
+
+- The user wants to install a .NET tool to their PATH
+- The user wants to list, update, remove, or search for .NET tools
+- The user wants to run a .NET tool without installing it (npx-style)
+- The user needs help setting up dotnet-install itself
+
+## When Not to Use
+
+- The user is managing NuGet package references in a project (use `dotnet add package`)
+- The user wants the traditional `dotnet tool install -g` workflow
+- The user is working with .NET SDKs or runtimes (use `dotnet-install.sh` from Microsoft)
+
+## Check if dotnet-install is available
+
+```bash
+dotnet-install --version
+```
+
+If not installed, install it:
+
+```bash
+# Option 1: via dotnet tool (requires .NET 10+ SDK)
+dotnet tool install -g dotnet-install
+dotnet-install setup
+
+# Option 2: install script (Unix only, no SDK required)
+curl -sSfL https://github.com/richlander/dotnet-install/raw/refs/heads/main/install.sh | sh
+```
+
+If already installed, update to the latest version:
+
+```bash
+dotnet-install update dotnet-install
+```
+
+## Install modes
+
+### From NuGet (pre-built, no SDK required)
+
+```bash
+dotnet-install --package dotnetsay
+dotnet-install --package dotnet-counters@9.0.0
+```
+
+### From GitHub (clones and builds)
+
+Requires git and .NET SDK.
+
+```bash
+dotnet-install --github richlander/dotnetsay
+dotnet-install --github owner/repo@v1.0 --ssh
+```
+
+### From local source (builds)
+
+Requires .NET SDK.
+
+```bash
+dotnet-install .                    # current directory
+dotnet-install src/my-tool          # subdirectory
+dotnet-install app.cs               # file-based app (.NET 10+)
+```
+
+### Positional args (auto-classified)
+
+```bash
+dotnet-install dotnetsay                  # bare name → NuGet
+dotnet-install richlander/dotnetsay       # owner/repo → GitHub
+dotnet-install ./src/tool                 # local path → source build
+```
+
+Use explicit flags (`--package`, `--github`) for
+non-interactive and CI environments.
+
+## Subcommands
+
+```bash
+dotnet-install ls                  # list installed tools
+dotnet-install rm <tool>           # remove a tool
+dotnet-install update [tool]       # update one or all tools
+dotnet-install search <query>      # search NuGet for tool packages
+dotnet-install info <tool>         # show tool details and provenance
+dotnet-install outdated            # check for newer versions
+dotnet-install run <pkg> [args]    # run without installing (npx-style)
+dotnet-install doctor [--fix]      # diagnose and fix PATH/config
+dotnet-install env                 # print environment info
+dotnet-install config [key] [val]  # view/set configuration
+dotnet-install completion <shell>  # shell completion setup
+```
+
+## Install directory
+
+Tools are installed to `~/.dotnet/bin/` by default.
+
+| Override | Effect |
+|----------|--------|
+| `-o <dir>` | Custom output directory |
+| `--local-bin` | Use `~/.local/bin/` instead |
+| `DOTNET_INSTALL_HOME` env var | Persistent override |
+
+## Configuration
+
+```bash
+dotnet-install config                         # show all settings
+dotnet-install config tip.quiet true          # suppress PATH tips
+dotnet-install config manage-global-tools true  # drain dotnet global tools via doctor
+```
+
+## Behavior notes
+
+- NuGet installs handle pointer packages (meta-packages
+  that redirect to RID-specific binaries) automatically
+- NativeAOT single-file binaries are placed directly in
+  the install dir; managed tools use a `_<name>/`
+  subdirectory with a symlink or `.cmd` shim
+- `run` downloads to a cache, executes, and does not
+  install permanently
+- Package signatures are verified when present
+- Missing prereqs (git, .NET SDK) produce actionable
+  error messages with install links