Compile-time Guppy template support.

use Guppy.Component imports the ~GUI sigil and common window assign/update helpers, compiling a restricted HEEx-style template syntax directly to Guppy IR.

The current template vocabulary intentionally matches Guppy's real IR surface:

• <div>
• <text>
• <rich_text />
• <button>
• <checkbox />
• <radio />
• <scroll>
• <uniform_list />
• <list />
• <data_table />
• <tree />
• <canvas />
• <popover>
• <select />
• <image />
• <icon />
• <spacer />
• <text_input />
• <textarea />

It also supports first-pass function components:

• dotted local tags like <.my_component> call a function in the current module with an assigns map
• remote module tags call render/1 on that module
• nested component content is passed as @children
• prop/4 can declare required props, defaults, and simple validations

Expressions use {...} syntax. Assign lookups use @name, resolving from an assigns map in scope when it is a map, otherwise from a Guppy.Window value named window.