feat: port CLI, TUI, and launcher from v1.5 into v2 (#1452)

Ports the CLI, TUI, and launcher from v1.5 into v2 behind a single
`mcp-inspector` entrypoint (launcher → web/cli/tui). Includes the
`mcp-inspector --web --dev` launcher fix (Vite alias resolution + prod-server
double-start), the root `postinstall` install cascade with simplified CI, and
spec/AGENTS docs (no-workspaces rationale, Development setup).

Closes #1246.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

clients/tui/README.md

@@ -0,0 +1,57 @@
+# MCP Inspector TUI Client
+
+The Terminal User Interface (TUI) client brings the interactive exploration capabilities of the Web Client directly to your terminal. It is built using [Ink](https://github.com/vadimdemedes/ink) to provide a rich, React-like component experience in a command-line environment.
+
+![MCP Inspector TUI Screenshot](../../docs/images/tui-screenshot.png)
+
+## Running the TUI
+
+You can run the TUI client via `npx`:
+
+```bash
+npx @modelcontextprotocol/inspector --tui node build/index.js
+```
+
+### With Configuration Files
+
+The TUI can load all servers from an MCP config file:
+
+```bash
+npx @modelcontextprotocol/inspector --tui --config mcp.json
+```
+
+(It does not use `--server`; all servers in the file are available in the TUI.)
+
+## Options
+
+### MCP server (which server(s) to connect to)
+
+Options that specify the MCP server(s) (config file, ad-hoc command/URL, env vars, headers) are shared by the Web, CLI, and TUI and are documented in [MCP server configuration](../../docs/mcp-server-configuration.md): `--config`, `-e`, `--cwd`, `--header`, `--transport`, `--server-url`, and the positional `[target...]`.
+
+### TUI-specific (OAuth for HTTP servers)
+
+When connecting to SSE or Streamable HTTP servers that use OAuth, you can pass:
+
+| Option                        | Description                                                                          |
+| ----------------------------- | ------------------------------------------------------------------------------------ |
+| `--client-id <id>`            | OAuth client ID (static client).                                                     |
+| `--client-secret <secret>`    | OAuth client secret (confidential clients).                                          |
+| `--client-metadata-url <url>` | OAuth Client ID Metadata Document URL (CIMD).                                        |
+| `--callback-url <url>`        | OAuth redirect/callback listener URL (default: `http://127.0.0.1:0/oauth/callback`). |
+
+## Features
+
+The TUI provides terminal-native tabs and panes for interacting with your MCP server:
+
+- **Resources**: Browse and read resources exposed by the server.
+- **Prompts**: List and test prompts.
+- **Tools**: View available tools and execute them with form-like inputs.
+- **History**: View the request and response history of your interactions.
+- **Console**: View the direct stdout/stderr and diagnostic logging of the connected server.
+
+## Navigation
+
+- Use the **Arrow Keys** (Left/Right) or **Tab** to switch between the main tabs (Resources, Tools, Prompts, etc.).
+- Use the **Arrow Keys** (Up/Down) to scroll through lists of items.
+- Press **Enter** to select an item, execute a tool, or fetch a resource.
+- Press **Escape** or `Ctrl+C` to exit the application.