docs: add HTTPS install options for all 6 platforms

Every platform now supports direct HTTPS installation:
- Claude Code: /plugin marketplace add https://github.com/...
- Codex: codex extensions add https://github.com/...
- OpenCode: npx opencode plugin install https://github.com/...
- Gemini CLI: gemini extensions install https://github.com/...
- Copilot CLI: copilot plugin install https://github.com/...
- Qwen Code: qwen extensions install https://github.com/...

Co-authored-by: Qwen-Coder <qwen-coder@alibabacloud.com>

Author: noah-sheldon

README.md

@@ -27,39 +27,68 @@ Think of it as a **system prompt that scales to 59 specialized skills and 33 dom
 /plugin install ai-dev-kit@ai-dev-kit
 ```
 
+Or install directly via HTTPS:
+
+```bash
+/plugin marketplace add https://github.com/noah-sheldon/ai-dev-kit
+/plugin install ai-dev-kit@ai-dev-kit
+```
+
 ### Codex
 
-Restart Codex after cloning this repo. The marketplace at `.agents/plugins/marketplace.json` will be discovered automatically.
+```bash
+codex extensions add https://github.com/noah-sheldon/ai-dev-kit
+```
+
+Or clone and discover automatically:
+
+```bash
+git clone https://github.com/noah-sheldon/ai-dev-kit
+```
+
+The marketplace at `.agents/plugins/marketplace.json` will be discovered automatically.
 
 ### OpenCode
 
 ```bash
 cd .opencode/plugins && npm install && npm run build
 ```
 
+Or install via HTTPS:
+
+```bash
+npx opencode plugin install https://github.com/noah-sheldon/ai-dev-kit
+```
+
 ### Gemini CLI
 
 ```bash
-gemini extensions link .
+gemini extensions link https://github.com/noah-sheldon/ai-dev-kit
+```
+
+Or install via HTTPS directly:
+
+```bash
+gemini extensions install https://github.com/noah-sheldon/ai-dev-kit
 ```
 
 ### GitHub Copilot CLI
 
 ```bash
-copilot plugin marketplace add noah-sheldon/ai-dev-kit
+copilot plugin marketplace add https://github.com/noah-sheldon/ai-dev-kit
 copilot plugin install ai-dev-kit@ai-dev-kit
 ```
 
-Or install directly from the repo:
+Or install via HTTPS shorthand:
 
 ```bash
-copilot plugin install noah-sheldon/ai-dev-kit:.github-copilot
+copilot plugin install https://github.com/noah-sheldon/ai-dev-kit
 ```
 
 ### Qwen Code
 
 ```bash
-qwen extensions install noah-sheldon/ai-dev-kit
+qwen extensions install https://github.com/noah-sheldon/ai-dev-kit
 ```
 
 Or install locally: