feat: centralize default constants and refactor overlay enter handling in TUI

apps/domain/src/agent/defaults.rs

@@ -0,0 +1,34 @@
+//! Shared default constants used across the application.
+//!
+//! Centralising these values eliminates the hardcoded-string duplication
+//! that existed when every call site provided its own inline fallback.
+//! Consumers should reference these constants rather than repeating
+//! the string literals.
+
+/// Default LLM provider API base URL.
+pub const DEFAULT_API_BASE: &str = "https://opencode.ai/zen/v1";
+
+/// Default LLM model identifier.
+pub const DEFAULT_MODEL: &str = "deepseek-v4-flash-free";
+
+/// Fallback JWT secret used only when `JWT_SECRET` env var is unset.
+/// In production this MUST be configured via environment variable.
+pub const FALLBACK_JWT_SECRET: &str = "dev-secret";
+
+/// Default context window size (128k tokens).
+pub const DEFAULT_CONTEXT_WINDOW: usize = 256_000;
+
+/// Maximum tool-call iterations per agent turn.
+pub const MAX_TOOL_ITERATIONS: u32 = 50;
+
+/// Maximum subagent tool-call iterations.
+pub const MAX_SUBAGENT_ITERATIONS: u32 = 25;
+
+/// Default LLM request max tokens.
+pub const DEFAULT_MAX_TOKENS: u32 = 4096;
+
+/// Default temperature for the main agent.
+pub const DEFAULT_TEMPERATURE: f64 = 0.7;
+
+/// Default temperature for compaction / summary calls.
+pub const DEFAULT_COMPACT_TEMPERATURE: f64 = 0.3;

apps/domain/src/agent/mod.rs

@@ -6,6 +6,7 @@ use std::path::PathBuf;
 
 use crate::core::{ChatMessage, ToolCallResult, UsageStats};
 
+pub mod defaults;
 pub mod prompt;
 pub mod progress;
 

apps/domain/src/lib.rs

@@ -57,6 +57,7 @@ pub use error::DomainError;
 // Agent module top-level items (TurnEvent, SessionRuntime, etc.)
 pub use agent::*;
 // Sub-module items need explicit re-exports
+pub use agent::defaults::*;
 pub use agent::progress::AgentProgress;
 pub use agent::prompt::{compaction_prompt, main_agent_prompt, subagent_directive};
 pub use workflow::*;

apps/domain/src/subagent/mod.rs

@@ -1,31 +1,5 @@
 //! Subagent domain models.
 
-/// Events emitted by a running subagent.
-#[derive(Debug, Clone)]
-pub enum SubagentEvent {
-    Started {
-        agent_id: String,
-        directive: String,
-    },
-    ToolCall {
-        agent_id: String,
-        tool_name: String,
-    },
-    ToolResult {
-        agent_id: String,
-        tool_name: String,
-        output: String,
-    },
-    Completed {
-        agent_id: String,
-        output: String,
-    },
-    Failed {
-        agent_id: String,
-        error: String,
-    },
-}
-
 /// Access tier for subagent tool permissions.
 ///
 /// Tiers are cumulative: `Write` includes everything in `Read`, and `Full`