feat(tui): complete TUI alignment with CCB — Steps 2-5

Step 2 — Keybindings (11 new actions):
  HistorySearch(Ctrl+R), ExternalEditor(Ctrl+G), Stash(Ctrl+S),
  ToggleTodos(Ctrl+T), ToggleTranscript(Ctrl+O), Redraw(Ctrl+L),
  KillAgents(Ctrl+K), CycleMode(Shift+Tab), ModelPicker(Alt+P),
  ImagePaste(Alt+V/Ctrl+V), Undo(Ctrl+Z/Ctrl+_)

Step 3 — Terminal capabilities:
  EnableBracketedPaste, EnableMouseCapture, EnableFocusChange
  with proper teardown in reverse order

Step 4 — Thinking state:
  ThinkingState enum (Idle/Thinking/ThoughtFor), 2s minimum display,
  elapsed time counter, auto-expiry on tick

Step 5 — Unseen messages + PromptInputMode:
  Scroll anchor tracking, "N new messages" divider rendering,
  PromptInputMode (Bash/Prompt/OrphanedPermission/TaskNotification),
  mode indicator prefix in input area, Shift+Tab cycling

Also fix all remaining ToolContext constructions missing ext field
across test files (integration_m3, integration_m7b, etc.)

Author: lingcoder

crates/agent/tests/integration_m7b.rs

@@ -172,6 +172,7 @@ async fn agent_tool_produces_spawn_request() {
         session_id: "e2e_test".into(),
         cancellation_token: tokio_util::sync::CancellationToken::new(),
         permission_policy: PermissionPolicy::default(),
+        ext: crab_core::tool::ToolContextExt::default(),
     };
 
     let input = serde_json::json!({
@@ -291,6 +292,7 @@ async fn tool_chain_write_then_edit() {
         session_id: "chain_test".into(),
         cancellation_token: tokio_util::sync::CancellationToken::new(),
         permission_policy: PermissionPolicy::default(),
+        ext: crab_core::tool::ToolContextExt::default(),
     };
 
     // Step 1: Write a file
@@ -337,6 +339,7 @@ async fn tool_chain_glob_then_read() {
         session_id: "glob_test".into(),
         cancellation_token: tokio_util::sync::CancellationToken::new(),
         permission_policy: PermissionPolicy::default(),
+        ext: crab_core::tool::ToolContextExt::default(),
     };
 
     // Step 1: Glob for .rs files
@@ -379,6 +382,7 @@ async fn permission_denied_tool_blocked() {
             allowed_tools: Vec::new(),
             denied_tools: vec![BASH_TOOL_NAME.into()],
         },
+        ext: crab_core::tool::ToolContextExt::default(),
     };
 
     let output = executor

crates/core/src/tool.rs

@@ -408,6 +408,7 @@ mod tests {
             session_id: "sess_123".into(),
             cancellation_token: CancellationToken::new(),
             permission_policy: PermissionPolicy::default(),
+            ext: crab_core::tool::ToolContextExt::default(),
         };
         assert_eq!(ctx.working_dir, std::path::Path::new("/tmp"));
         assert_eq!(ctx.permission_mode, PermissionMode::Default);

crates/tools/src/builtin/bash.rs

@@ -401,6 +401,7 @@ mod tests {
             session_id: "test".into(),
             cancellation_token: CancellationToken::new(),
             permission_policy: PermissionPolicy::default(),
+            ext: crab_core::tool::ToolContextExt::default(),
         }
     }
 

crates/tools/src/builtin/image_read.rs

@@ -144,6 +144,7 @@ mod tests {
             session_id: "test".into(),
             cancellation_token: CancellationToken::new(),
             permission_policy: crab_core::permission::PermissionPolicy::default(),
+            ext: crab_core::tool::ToolContextExt::default(),
         }
     }
 

crates/tools/src/builtin/mcp_tool.rs

@@ -296,6 +296,7 @@ mod tests {
             session_id: "test".into(),
             cancellation_token: tokio_util::sync::CancellationToken::new(),
             permission_policy: crab_core::permission::PermissionPolicy::default(),
+            ext: crab_core::tool::ToolContextExt::default(),
         };
 
         let output = adapter
@@ -339,6 +340,7 @@ mod tests {
             session_id: "test".into(),
             cancellation_token: tokio_util::sync::CancellationToken::new(),
             permission_policy: crab_core::permission::PermissionPolicy::default(),
+            ext: crab_core::tool::ToolContextExt::default(),
         };
 
         let output = adapter.execute(serde_json::json!({}), &ctx).await.unwrap();

crates/tools/src/builtin/powershell.rs

@@ -164,6 +164,7 @@ mod tests {
             session_id: "test".into(),
             cancellation_token: CancellationToken::new(),
             permission_policy: PermissionPolicy::default(),
+            ext: crab_core::tool::ToolContextExt::default(),
         }
     }
 

crates/tools/tests/integration_m3.rs

@@ -32,6 +32,7 @@ fn make_ctx(working_dir: &Path, mode: PermissionMode) -> ToolContext {
             allowed_tools: vec![],
             denied_tools: vec![],
         },
+        ext: crab_core::tool::ToolContextExt::default(),
     }
 }