Add mechanicus-thinking-label extension

Monkey-patches AssistantMessageComponent.updateContent to swap the
default "Thinking..." label for "Cogitating..." when reasoning blocks
are folded. Only replaces the default — if any code path sets its own
label, we leave it alone.

Override via PI_THINKING_LABEL env var.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

.gitignore

@@ -13,5 +13,6 @@
 !/local-llama.ts
 !/markdown-body-color.ts
 !/mechanicus-banner.ts
+!/mechanicus-thinking-label.ts
 !/scripts/
 !/themes/

mechanicus-thinking-label.ts

@@ -0,0 +1,36 @@
+/**
+ * mechanicus-thinking-label — replace pi's "Thinking..." label with a
+ * dark-mechanicum one when assistant reasoning blocks are folded.
+ *
+ * pi's AssistantMessageComponent stores the label as an instance field
+ * initialised from the constructor default. pi-coding-agent never
+ * overrides it in its own code paths, so we can monkey-patch
+ * updateContent() to swap the default before rendering.
+ *
+ * Override via env var: PI_THINKING_LABEL="Cogitating…"
+ */
+
+import type { ExtensionAPI } from "@mariozechner/pi-coding-agent";
+import { AssistantMessageComponent } from "@mariozechner/pi-coding-agent";
+
+const DEFAULT_LABEL = "Thinking...";
+const LABEL = process.env.PI_THINKING_LABEL ?? "Cogitating...";
+
+let patched = false;
+
+export default function (_pi: ExtensionAPI) {
+	if (patched) return;
+	patched = true;
+
+	const proto = AssistantMessageComponent.prototype as any;
+	const origUpdate = proto.updateContent;
+
+	proto.updateContent = function (message: unknown) {
+		if (this.hiddenThinkingLabel === DEFAULT_LABEL) {
+			this.hiddenThinkingLabel = LABEL;
+		}
+		return origUpdate.call(this, message);
+	};
+
+	console.log(`[mechanicus-thinking-label] "${DEFAULT_LABEL}" -> "${LABEL}"`);
+}