feat(chat): restyle thinking — visible bubble, collapse, title swap, persisted open

Thinking renders inside a visible rounded-card bubble (like tool calls),
capped to the same max-w-5xl column as assistant text. Uses a DaisyUI
checkbox collapse (no arrow/plus icon) with smooth animation. Title reads
"Thinking" + loading-dots while the model is actively generating, then
flips to "Thoughts" with no dots once done. Open/closed state persists
across the generating→completed→sealed transition via stable ordinal keys
(per-conversation isolation via {#key} in App). Added optional streaming
flag to RenderedChunk (pure selector, only on the accumulating chunk).

3 files changed, 23 insertions, 1 deletions

diff --git a/src/core/chunks/reducer.test.ts b/src/core/chunks/reducer.test.ts
index 7ecc349..f2f1b75 100644
--- a/src/core/chunks/reducer.test.ts
+++ b/src/core/chunks/reducer.test.ts
@@ -371,6 +371,21 @@ describe("selectChunks", () => {
 		expect(chunks[0]?.provisional).toBe(true);
 		expect(chunks[0]?.chunk).toEqual({ type: "text", text: "building..." });
 	});
+
+	it("marks ONLY the actively-accumulating chunk as streaming", () => {
+		let s = initialState();
+		s = foldEvent(s, turnStart("t1"));
+		// A flushed-but-still-provisional thinking chunk, then a live accumulating one.
+		s = foldEvent(s, reasoningDelta("t1", "first thought"));
+		s = foldEvent(s, toolCall("t1", "tc1", "bash", {})); // flushes the thinking
+		s = foldEvent(s, textDelta("t1", "now writing"));
+		const chunks = selectChunks(s);
+		const thinking = chunks.find((c) => c.chunk.type === "thinking");
+		const accumulating = chunks.find((c) => c.streaming === true);
+		expect(thinking?.streaming).toBeFalsy(); // flushed → not streaming
+		expect(accumulating?.chunk).toEqual({ type: "text", text: "now writing" });
+		expect(chunks.filter((c) => c.streaming === true)).toHaveLength(1);
+	});
 });
 
 describe("selectMessages", () => {
diff --git a/src/core/chunks/selectors.ts b/src/core/chunks/selectors.ts
index 8fb832f..839ba65 100644
--- a/src/core/chunks/selectors.ts
+++ b/src/core/chunks/selectors.ts
@@ -18,7 +18,7 @@ export function selectChunks(state: TranscriptState): readonly RenderedChunk[] {
 			state.accumulating.kind === "text"
 				? { type: "text", text: state.accumulating.text }
 				: { type: "thinking", text: state.accumulating.text };
-		result.push({ seq: null, role: "assistant", chunk, provisional: true });
+		result.push({ seq: null, role: "assistant", chunk, provisional: true, streaming: true });
 	}
 	return result;
 }
diff --git a/src/core/chunks/types.ts b/src/core/chunks/types.ts
index 3792445..e031ce3 100644
--- a/src/core/chunks/types.ts
+++ b/src/core/chunks/types.ts
@@ -28,4 +28,11 @@ export interface RenderedChunk {
 	readonly role: Role;
 	readonly chunk: Chunk;
 	readonly provisional: boolean;
+	/**
+	 * True only for the single chunk currently being accumulated from live deltas
+	 * (the in-flight text/thinking the model is actively generating). Absent/false
+	 * once flushed or committed. Lets the UI show a live indicator (e.g. loading
+	 * dots on streaming thinking) and drop it the moment generation moves on.
+	 */
+	readonly streaming?: boolean;
 }