feat: enabled text-sizing and fixed OSC66 and DECCARA rendering behavior

- Added `textSizing` terminal capability and `tui.textSizing` setting for Kitty OSC66 scaling.
- Updated OSC66 range and visible-width handling to preserve grapheme slice behavior.
- Updated markdown rendering to apply heading text sizing only when enabled.
- Fixed DECCARA trailing-background fill tracking and DECRPM status 3/4 recognition.

packages/coding-agent/test/debug/protocol-probe.test.ts

@@ -1,6 +1,11 @@
-import { beforeAll, describe, expect, it } from "bun:test";
-import { getImageDimensions } from "@oh-my-pi/pi-tui";
-import { buildLargeTextLines, buildSampleImage, encodeRgbPng } from "../../src/debug/protocol-probe";
+import { afterEach, beforeAll, describe, expect, it } from "bun:test";
+import { getImageDimensions, ImageBudget, ImageProtocol, TERMINAL } from "@oh-my-pi/pi-tui";
+import {
+	buildLargeTextLines,
+	buildSampleImage,
+	encodeRgbPng,
+	ProtocolProbeComponent,
+} from "../../src/debug/protocol-probe";
 import { initTheme } from "../../src/modes/theme/theme";
 
 beforeAll(async () => {
@@ -8,6 +13,14 @@ beforeAll(async () => {
 	await initTheme();
 });
 
+type MutableTerminalInfo = { imageProtocol: ImageProtocol | null };
+const terminal = TERMINAL as unknown as MutableTerminalInfo;
+const originalImageProtocol = TERMINAL.imageProtocol;
+
+afterEach(() => {
+	terminal.imageProtocol = originalImageProtocol;
+});
+
 describe("encodeRgbPng / buildSampleImage", () => {
 	it("emits a PNG whose IHDR dimensions decode back to the requested size", () => {
 		// The graphics test relies on producing a *valid* PNG: Kitty/iTerm2 hand
@@ -30,6 +43,22 @@ describe("encodeRgbPng / buildSampleImage", () => {
 	});
 });
 
+it("uses independent graphics ids for repeated probe panels", () => {
+	terminal.imageProtocol = ImageProtocol.Kitty;
+	const budget = new ImageBudget(8, () => {});
+	const image = buildSampleImage(8, 8);
+	const first = new ProtocolProbeComponent({ image, imageBudget: budget, notificationSuppressed: true });
+	const second = new ProtocolProbeComponent({ image, imageBudget: budget, notificationSuppressed: true });
+
+	budget.beginPass();
+	const firstBytes = first.render(80).join("\n");
+	const secondBytes = second.render(80).join("\n");
+	budget.endPass();
+
+	expect(firstBytes).toContain("i=1");
+	expect(secondBytes).toContain("i=2");
+});
+
 describe("buildLargeTextLines", () => {
 	it("encodes each scale as an OSC 66 span and reserves scale-1 blank rows below it", () => {
 		const lines = buildLargeTextLines([2, 3]);