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/web/tsconfig.node.json

@@ -46,5 +46,5 @@
       "@napi-rs/keyring": ["./node_modules/@napi-rs/keyring"]
     }
   },
-  "include": ["vite.config.ts", "server/**/*.ts"]
+  "include": ["vite.config.ts", "tsup.runner.config.ts", "server/**/*.ts"]
 }