fix: propagate thinking level changes to existing components and use viewSession

Address 4 P2 review comments on PR #3314:

1. effectiveHideThinkingBlock now uses viewSession.thinkingLevel
   instead of session.thinkingLevel — in focused-agent mode, the
   viewed transcript may have a different thinking level than the
   main session.

2. thinking_level_changed handler now iterates existing
   AssistantMessageComponent children and calls setHideThinkingBlock
   with the new effective value, then resetDisplay() to repaint.
   Previously only new/streaming messages got the updated visibility.

3. Changed AssistantMessageComponent import from type-only to value
   import for instanceof check.

4. Agent Hub callback already uses effectiveHideThinkingBlock which
   now reflects viewSession — no separate fix needed.

Author: oldschoola

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

@@ -5,7 +5,7 @@ import { INTENT_FIELD } from "@oh-my-pi/pi-wire";
 import { extractTextContent } from "../../commit/utils";
 import { settings } from "../../config/settings";
 import { getFileSnapshotStore } from "../../edit/file-snapshot-store";
-import type { AssistantMessageComponent } from "../../modes/components/assistant-message";
+import { AssistantMessageComponent } from "../../modes/components/assistant-message";
 import { detectCacheInvalidation } from "../../modes/components/cache-invalidation-marker";
 import {
 	ReadToolGroupComponent,
@@ -120,7 +120,20 @@ export class EventController {
 			thinking_level_changed: async () => {
 				this.ctx.statusLine.invalidate();
 				this.ctx.updateEditorBorderColor();
-				this.ctx.ui.requestRender();
+				// Propagate visibility to existing rendered messages — thinking level
+				// changes mid-session must update already-rendered AssistantMessageComponents,
+				// not just new ones. Streaming reads effectiveHideThinkingBlock at construction.
+				const hideThinking = this.ctx.effectiveHideThinkingBlock;
+				for (const child of this.ctx.chatContainer.children) {
+					if (child instanceof AssistantMessageComponent) {
+						child.setHideThinkingBlock(hideThinking);
+					}
+				}
+				if (this.ctx.streamingComponent && this.ctx.streamingMessage) {
+					this.ctx.streamingComponent.setHideThinkingBlock(hideThinking);
+					this.ctx.streamingComponent.updateContent(this.ctx.streamingMessage);
+				}
+				this.ctx.ui.resetDisplay();
 			},
 			goal_updated: async () => {},
 		} satisfies AgentSessionEventHandlers;

packages/coding-agent/src/modes/interactive-mode.ts

@@ -414,7 +414,7 @@ export class InteractiveMode implements InteractiveModeContext {
 	 * respects the user's intent when they set thinking to "off" (#626).
 	 */
 	get effectiveHideThinkingBlock(): boolean {
-		return this.hideThinkingBlock || (this.session?.thinkingLevel ?? ThinkingLevel.Off) === ThinkingLevel.Off;
+		return this.hideThinkingBlock || (this.viewSession?.thinkingLevel ?? ThinkingLevel.Off) === ThinkingLevel.Off;
 	}
 	proseOnlyThinking = true;
 	compactionQueuedMessages: CompactionQueuedMessage[] = [];