feat: add ephemeral /btw side-question panel (#399)

* feat: add ephemeral /btw side-question panel

* fix: preserve /btw live context and payload hooks

* fix: send /btw question through session pipeline

packages/coding-agent/src/modes/controllers/input-controller.ts

@@ -29,6 +29,7 @@ export class InputController {
 		this.ctx.editor.shouldBypassAutocompleteOnEscape = () =>
 			Boolean(
 				this.ctx.loadingAnimation ||
+					this.ctx.hasActiveBtw() ||
 					this.ctx.session.isStreaming ||
 					this.ctx.session.isCompacting ||
 					this.ctx.session.isGeneratingHandoff ||
@@ -40,6 +41,9 @@ export class InputController {
 					this.ctx.retryEscapeHandler,
 			);
 		this.ctx.editor.onEscape = () => {
+			if (this.ctx.hasActiveBtw() && this.ctx.handleBtwEscape()) {
+				return;
+			}
 			if (this.ctx.loadingAnimation) {
 				if (this.ctx.cancelPendingSubmission()) {
 					return;
@@ -435,6 +439,9 @@ export class InputController {
 			this.ctx.showWarning("Agent is idle; nothing to background");
 			return;
 		}
+		if (this.ctx.hasActiveBtw()) {
+			this.ctx.handleBtwEscape();
+		}
 
 		this.ctx.isBackgrounded = true;
 		const backgroundUiContext = this.ctx.createBackgroundUiContext();