[Feature] Text rendeirng pipeline

[vmarcella]

Overview

Create a rendering pipeline that draws laid-out text using the glyph atlas,
producing visible text on screen.

Current State

No response

Scope

Goals:

• Shader for rendering atlas glyphs
• Batch multiple text draws efficiently
• Support text color
• Integrate with existing render command system

Non-Goals:

• Text effects (shadows, outlines)
• SDF rendering

Proposed API

pub struct TextRenderer {
  pipeline: ResourceId,
  vertex_buffer: Buffer,
  bind_group: ResourceId,
}

impl TextRenderer {
  pub fn new(render_context: &mut RenderContext, atlas: &GlyphAtlas) -> Self;
  
  pub fn draw(
    &mut self,
    layout: &TextLayout,
    position: [f32; 2],
    color: [f32; 4],
  ) -> Vec<RenderCommand>;
  
  pub fn update_atlas(&mut self, atlas: &GlyphAtlas);
}

// Or integrated with RenderContext
impl RenderContext {
  pub fn draw_text(
    &mut self,
    text: &str,
    font: Handle<Font>,
    size: f32,
    position: [f32; 2],
    color: [f32; 4],
  ) -> Vec<RenderCommand>;
}

Acceptance Criteria

• Text renders at correct position
• Text color applies correctly
• Multiple text draws batch together
• Transparent background (alpha blending)
• Example rendering "Hello World"

Affected Crates

lambda-rs

Notes

• Use instancing for glyph quads
• Alpha blending required for smooth edges