feat: added /rename command to set session titles for status/header/tab display

- Added `/rename <title>` slash command to set explicit session names and update header/tab titles.
- Added `session_name` status segment with hash-derived accent color for session titles.
- Fixed shell execution failure sanitization to preserve all `execResult` fields after redacting stderr.
- Fixed tool execution completion output to pass original `toolResult` text instead of sanitized `content`.

scripts/host-detect.ts

@@ -0,0 +1,43 @@
+import * as fs from "node:fs";
+
+function runCommand(command: string, args: string[]): string | null {
+	try {
+		const result = Bun.spawnSync([command, ...args], { stdout: "pipe", stderr: "pipe" });
+		if (result.exitCode !== 0) return null;
+		return result.stdout.toString("utf-8").trim();
+	} catch {
+		return null;
+	}
+}
+
+export function detectHostAvx2Support(): boolean {
+	if (process.arch !== "x64") return false;
+
+	if (process.platform === "linux") {
+		try {
+			const cpuInfo = fs.readFileSync("/proc/cpuinfo", "utf8");
+			return /\bavx2\b/i.test(cpuInfo);
+		} catch {
+			return false;
+		}
+	}
+
+	if (process.platform === "darwin") {
+		const leaf7 = runCommand("sysctl", ["-n", "machdep.cpu.leaf7_features"]);
+		if (leaf7 && /\bAVX2\b/i.test(leaf7)) return true;
+		const features = runCommand("sysctl", ["-n", "machdep.cpu.features"]);
+		return Boolean(features && /\bAVX2\b/i.test(features));
+	}
+
+	if (process.platform === "win32") {
+		const output = runCommand("powershell.exe", [
+			"-NoProfile",
+			"-NonInteractive",
+			"-Command",
+			"[System.Runtime.Intrinsics.X86.Avx2]::IsSupported",
+		]);
+		return output?.toLowerCase() === "true";
+	}
+
+	return false;
+}