feat: add Dioxus and GPUI UI prototypes for framework comparison

Dioxus (ui-dioxus/): 2,169 lines, WebView mode (same wry as Tauri),
  Catppuccin theme, 12 components, agor-core integration, compiles clean.
  Evolution path — keeps xterm.js, gradual migration from Tauri.

GPUI (ui-gpui/): 2,490 lines, GPU-accelerated rendering, alacritty_terminal
  for native terminal, 17 files, Catppuccin palette, demo data.
  Revolution path — pure Rust UI, 120fps target, no WebView.

Both are standalone (not in workspace), share agor-core backend.
Created for side-by-side comparison to inform framework decision.

ui-gpui/src/state.rs

@@ -0,0 +1,262 @@
+//! Application state — projects, agents, settings.
+//!
+//! All mutable state lives in `AppState`, wrapped in `Entity<AppState>` for
+//! GPUI reactivity. Components read via `entity.read(cx)` and mutate via
+//! `entity.update(cx, |state, cx| { ... cx.notify(); })`.
+
+use serde::{Deserialize, Serialize};
+use uuid::Uuid;
+
+// ── Agent Message Types ─────────────────────────────────────────────
+
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub enum MessageRole {
+    User,
+    Assistant,
+    System,
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct AgentMessage {
+    pub id: String,
+    pub role: MessageRole,
+    pub content: String,
+    pub timestamp: u64,
+    /// For tool calls: the tool name.
+    pub tool_name: Option<String>,
+    /// For tool results: the result content.
+    pub tool_result: Option<String>,
+    /// Whether this message block is collapsed in the UI.
+    pub collapsed: bool,
+}
+
+// ── Agent State ─────────────────────────────────────────────────────
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
+pub enum AgentStatus {
+    Idle,
+    Running,
+    Done,
+    Error,
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct AgentSession {
+    pub session_id: String,
+    pub status: AgentStatus,
+    pub messages: Vec<AgentMessage>,
+    pub cost_usd: f64,
+    pub tokens_used: u64,
+    pub model: String,
+}
+
+impl AgentSession {
+    pub fn new() -> Self {
+        Self {
+            session_id: Uuid::new_v4().to_string(),
+            status: AgentStatus::Idle,
+            messages: Vec::new(),
+            cost_usd: 0.0,
+            tokens_used: 0,
+            model: "claude-sonnet-4-20250514".to_string(),
+        }
+    }
+}
+
+// ── Project ─────────────────────────────────────────────────────────
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
+pub enum ProjectTab {
+    Model,
+    Docs,
+    Files,
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct Project {
+    pub id: String,
+    pub name: String,
+    pub cwd: String,
+    pub active_tab: ProjectTab,
+    pub agent: AgentSession,
+    /// Accent color index (cycles through palette).
+    pub accent_index: usize,
+}
+
+impl Project {
+    pub fn new(name: &str, cwd: &str, accent_index: usize) -> Self {
+        Self {
+            id: Uuid::new_v4().to_string(),
+            name: name.to_string(),
+            cwd: cwd.to_string(),
+            active_tab: ProjectTab::Model,
+            agent: AgentSession::new(),
+            accent_index,
+        }
+    }
+}
+
+// ── Settings ────────────────────────────────────────────────────────
+
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct Settings {
+    pub theme: String,
+    pub ui_font_family: String,
+    pub ui_font_size: f32,
+    pub term_font_family: String,
+    pub term_font_size: f32,
+    pub default_shell: String,
+    pub default_cwd: String,
+}
+
+impl Default for Settings {
+    fn default() -> Self {
+        Self {
+            theme: "Catppuccin Mocha".to_string(),
+            ui_font_family: "Inter".to_string(),
+            ui_font_size: 14.0,
+            term_font_family: "JetBrains Mono".to_string(),
+            term_font_size: 14.0,
+            default_shell: std::env::var("SHELL").unwrap_or_else(|_| "/bin/bash".to_string()),
+            default_cwd: dirs::home_dir()
+                .map(|p| p.to_string_lossy().to_string())
+                .unwrap_or_else(|| "/".to_string()),
+        }
+    }
+}
+
+// ── Command Palette ─────────────────────────────────────────────────
+
+#[derive(Debug, Clone)]
+pub struct PaletteCommand {
+    pub id: &'static str,
+    pub label: &'static str,
+    pub shortcut: Option<&'static str>,
+}
+
+pub fn all_commands() -> Vec<PaletteCommand> {
+    vec![
+        PaletteCommand {
+            id: "settings",
+            label: "Open Settings",
+            shortcut: Some("Ctrl+,"),
+        },
+        PaletteCommand {
+            id: "new_project",
+            label: "Add Project",
+            shortcut: Some("Ctrl+N"),
+        },
+        PaletteCommand {
+            id: "toggle_sidebar",
+            label: "Toggle Sidebar",
+            shortcut: Some("Ctrl+B"),
+        },
+        PaletteCommand {
+            id: "focus_next",
+            label: "Focus Next Project",
+            shortcut: Some("Ctrl+]"),
+        },
+        PaletteCommand {
+            id: "focus_prev",
+            label: "Focus Previous Project",
+            shortcut: Some("Ctrl+["),
+        },
+        PaletteCommand {
+            id: "close_project",
+            label: "Close Focused Project",
+            shortcut: None,
+        },
+        PaletteCommand {
+            id: "restart_agent",
+            label: "Restart Agent",
+            shortcut: None,
+        },
+        PaletteCommand {
+            id: "stop_agent",
+            label: "Stop Agent",
+            shortcut: None,
+        },
+    ]
+}
+
+// ── Root Application State ──────────────────────────────────────────
+
+pub struct AppState {
+    pub projects: Vec<Project>,
+    pub focused_project_idx: Option<usize>,
+    pub settings: Settings,
+    pub sidebar_open: bool,
+    pub settings_open: bool,
+    pub palette_open: bool,
+    pub palette_query: String,
+}
+
+impl AppState {
+    /// Create initial state with demo projects.
+    pub fn new_demo() -> Self {
+        Self {
+            projects: vec![
+                Project::new("agent-orchestrator", "~/code/ai/agent-orchestrator", 0),
+                Project::new("quanta-discord-bot", "~/code/quanta-discord-bot", 1),
+            ],
+            focused_project_idx: Some(0),
+            settings: Settings::default(),
+            sidebar_open: true,
+            settings_open: false,
+            palette_open: false,
+            palette_query: String::new(),
+        }
+    }
+
+    pub fn focused_project(&self) -> Option<&Project> {
+        self.focused_project_idx
+            .and_then(|i| self.projects.get(i))
+    }
+
+    pub fn focused_project_mut(&mut self) -> Option<&mut Project> {
+        self.focused_project_idx
+            .and_then(|i| self.projects.get_mut(i))
+    }
+
+    pub fn toggle_sidebar(&mut self) {
+        self.sidebar_open = !self.sidebar_open;
+    }
+
+    pub fn toggle_settings(&mut self) {
+        self.settings_open = !self.settings_open;
+    }
+
+    pub fn toggle_palette(&mut self) {
+        self.palette_open = !self.palette_open;
+        if self.palette_open {
+            self.palette_query.clear();
+        }
+    }
+
+    /// Filtered palette commands based on current query.
+    pub fn filtered_commands(&self) -> Vec<PaletteCommand> {
+        let q = self.palette_query.to_lowercase();
+        all_commands()
+            .into_iter()
+            .filter(|cmd| q.is_empty() || cmd.label.to_lowercase().contains(&q))
+            .collect()
+    }
+
+    /// Total running agents.
+    pub fn running_agent_count(&self) -> usize {
+        self.projects
+            .iter()
+            .filter(|p| p.agent.status == AgentStatus::Running)
+            .count()
+    }
+
+    /// Total cost across all agents.
+    pub fn total_cost(&self) -> f64 {
+        self.projects.iter().map(|p| p.agent.cost_usd).sum()
+    }
+
+    /// Total tokens across all agents.
+    pub fn total_tokens(&self) -> u64 {
+        self.projects.iter().map(|p| p.agent.tokens_used).sum()
+    }
+}