feat: add select, file_path, and directory_path input types - #121

Summary

• Add rendering for select, file_path, and directory_path input types in the server configuration UI
• select renders a dropdown from predefined options on the input definition
• file_path and directory_path render a text input with a native file/directory picker button via tauri-plugin-dialog
• Update InputDefinition TypeScript type with new type union and options field
• Remove password input type (replaced by text + secret: true)
• Fix clippy warning in shell_env.rs (conditional #[cfg(unix)] import)

Changes

• ServersPage.tsx: Add 3 new case branches in renderInput() switch
• registry.ts: Update InputDefinition.type union and add options field
• Cargo.toml / lib.rs / capabilities: Integrate tauri-plugin-dialog
• package.json: Add @tauri-apps/plugin-dialog dependency
• tests/ts/setup.ts: Add dialog plugin mock for test environment
• shell_env.rs: Gate tracing import behind #[cfg(unix)]

Test plan

• Verify select dropdown renders with options for servers like Playwright (browser select)
• Verify file_path picker opens native file dialog and populates the text input
• Verify directory_path picker opens native directory dialog and populates the text input
• Verify text + secret: true still renders as password input (replacing old password type)
• Run pnpm test:ts — existing tests pass with new dialog mock