docs: add some ui-related guides

generated using code2prompt + claude 3.7 sonnet

Signed-off-by: William Casarin <jb55@jb55.com>

crates/notedeck_ui/README.md

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+# NoteDeck UI
+
+UI component library for NoteDeck - a Nostr client built with EGUI.
+
+## Overview
+
+The `notedeck_ui` crate provides a set of reusable UI components for building a Nostr client. It offers consistent styling, behavior, and rendering of Nostr-specific elements like notes, profiles, mentions, and media content.
+
+This library is built on top of [egui](https://github.com/emilk/egui), a simple, fast, and highly portable immediate mode GUI library for Rust.
+
+## Features
+
+- 📝 Note display with rich content, media, and interactions
+- 👤 Profile components (display name, pictures, banners)
+- 🔗 Mention system with hover previews
+- 🖼️ Image handling with caching and lazy loading
+- 📺 GIF playback support
+- 💸 Zap interactions (Bitcoin Lightning tips)
+- 🎨 Theming and consistent styling
+
+## Components
+
+### Notes
+
+The `NoteView` widget is the core component for displaying Nostr notes:
+
+```rust
+// Example: Render a note
+let mut note_view = NoteView::new(
+    note_context,
+    current_account,
+    &note, 
+    NoteOptions::default()
+);
+
+ui.add(&mut note_view);
+```
+
+`NoteView` supports various display options:
+
+```rust
+// Create a preview style note
+note_view
+    .preview_style()       // Apply preview styling
+    .textmode(true)        // Use text-only mode
+    .actionbar(false)      // Hide action bar
+    .small_pfp(true)       // Use small profile picture
+    .note_previews(false)  // Disable nested note previews
+    .show(ui);
+```
+
+### Profiles
+
+Profile components include profile pictures, banners, and display names:
+
+```rust
+// Display a profile picture
+ui.add(ProfilePic::new(images_cache, profile_picture_url).size(48.0));
+
+// Display a profile preview
+ui.add(ProfilePreview::new(profile_record, images_cache));
+```
+
+### Mentions
+
+The mention component links to user profiles:
+
+```rust
+// Display a mention with hover preview
+let mention_response = Mention::new(ndb, img_cache, txn, pubkey)
+    .size(16.0)            // Set text size
+    .selectable(true)      // Allow selection
+    .show(ui);
+
+// Handle click actions
+if let Some(action) = mention_response.inner {
+    // Handle profile navigation
+}
+```
+
+### Media
+
+Support for images, GIFs, and other media types:
+
+```rust
+// Render an image
+render_images(
+    ui,
+    img_cache,
+    image_url,
+    ImageType::Content,
+    cache_type,
+    on_loading_callback,
+    on_error_callback,
+    on_success_callback
+);
+```
+
+## Styling
+
+The UI components adapt to the current theme (light/dark mode) and use consistent styling defined in the `colors.rs` module:
+
+```rust
+// Color constants
+pub const ALMOST_WHITE: Color32 = Color32::from_rgb(0xFA, 0xFA, 0xFA);
+pub const MID_GRAY: Color32 = Color32::from_rgb(0xbd, 0xbd, 0xbd);
+pub const PINK: Color32 = Color32::from_rgb(0xE4, 0x5A, 0xC9);
+pub const TEAL: Color32 = Color32::from_rgb(0x77, 0xDC, 0xE1);
+```
+
+## Dependencies
+
+This crate depends on:
+- `egui` - Core UI library
+- `egui_extras` - Additional widgets and functionality
+- `ehttp` - HTTP client for fetching content
+- `nostrdb` - Nostr database and types
+- `enostr` - Nostr protocol implementation
+- `image` - Image processing library
+- `poll-promise` - Async promise handling
+- `tokio` - Async runtime