Simplify auth and search client, drop local JWT expiry tracking

Auth:
- Remove jwt.ts — stop decoding JWT exp claims locally
- Simplify OTP login: direct token extraction from verify response,
  remove CookieJar, BFS token extraction, session fallback, CF bypass
- Storage: drop expires field, store token-only; clear on 401/403
- Single auth path: try stored token → macOS app → OTP fallback

Search client:
- Remove Cloudflare subprocess fallback (fetchViaBunRuntime)
- Remove streamFromText, isCloudflareChallenge, BunFetchResult
- Simplify SSE fetch to single fetch() call with abort signal
- Let server validate tokens; clear cache on auth errors

Render:
- Extract shared utilities (asString, truncate) to render/util.ts
- Simplify call.ts and result.ts to import from shared module

Tests:
- Remove jwt.test.ts (module deleted)
- Add otp-flow.test.ts for email OTP authentication
- Simplify login and client tests for reduced code paths

Add debug scripts and plan documents.

src/render/call.ts

@@ -1,5 +1,6 @@
 import type { Theme } from "@mariozechner/pi-coding-agent";
 import { Text } from "@mariozechner/pi-tui";
+import { asString, asPositiveNumber, truncate } from "./util.js";
 
 interface PerplexityCallArgs {
   query?: unknown;
@@ -8,27 +9,6 @@ interface PerplexityCallArgs {
 }
 
 const RECENCY_VALUES = new Set(["hour", "day", "week", "month", "year"] as const);
-
-function asString(value: unknown): string | undefined {
-  return typeof value === "string" ? value : undefined;
-}
-
-function asPositiveNumber(value: unknown): number | undefined {
-  if (typeof value !== "number" || !Number.isFinite(value) || value <= 0) {
-    return undefined;
-  }
-
-  return value;
-}
-
-function truncate(text: string, maxLength: number): string {
-  if (text.length <= maxLength) {
-    return text;
-  }
-
-  return `${text.slice(0, Math.max(1, maxLength - 1))}…`;
-}
-
 export function renderPerplexityCall(args: PerplexityCallArgs, theme: Theme): Text {
   const query = asString(args?.query)?.trim();
   const recencyRaw = asString(args?.recency)?.trim().toLowerCase();

src/render/result.ts

@@ -1,5 +1,6 @@
 import type { AgentToolResult, Theme, ToolRenderResultOptions } from "@mariozechner/pi-coding-agent";
 import { Text } from "@mariozechner/pi-tui";
+import { asString, asNumber, truncate } from "./util.js";
 
 interface PerplexityResultDetails {
   model?: unknown;
@@ -9,23 +10,6 @@ interface PerplexityResultDetails {
   toolCallId?: unknown;
   error?: unknown;
 }
-
-function asString(value: unknown): string | undefined {
-  return typeof value === "string" ? value : undefined;
-}
-
-function asNumber(value: unknown): number | undefined {
-  return typeof value === "number" && Number.isFinite(value) ? value : undefined;
-}
-
-function truncate(text: string, maxLength: number): string {
-  if (text.length <= maxLength) {
-    return text;
-  }
-
-  return `${text.slice(0, Math.max(1, maxLength - 1))}…`;
-}
-
 function extractTextContent(result: AgentToolResult<PerplexityResultDetails>): string | undefined {
   if (!Array.isArray(result?.content)) {
     return undefined;
@@ -63,7 +47,11 @@ export function renderPerplexityResult(
   options: ToolRenderResultOptions,
   theme: Theme,
 ): Text {
-  const details = (result?.details ?? {}) as PerplexityResultDetails;
+  const raw = result?.details;
+  const details: PerplexityResultDetails =
+    raw && typeof raw === "object" && !Array.isArray(raw)
+      ? (raw as PerplexityResultDetails)
+      : {};
   const contentText = extractTextContent(result);
 
   if (options?.isPartial) {

src/render/util.ts

@@ -0,0 +1,28 @@
+export function asString(value: unknown): string | undefined {
+	return typeof value === "string" ? value : undefined;
+}
+
+/** Safely extract a message from an unknown caught value. */
+export function errorMessage(error: unknown): string {
+	if (error instanceof Error) return error.message;
+	if (typeof error === "string") return error;
+	return "Unknown error";
+}
+
+export function asNumber(value: unknown): number | undefined {
+	return typeof value === "number" && Number.isFinite(value) ? value : undefined;
+}
+
+export function asPositiveNumber(value: unknown): number | undefined {
+	if (typeof value !== "number" || !Number.isFinite(value) || value <= 0) {
+		return undefined;
+	}
+	return value;
+}
+
+export function truncate(text: string, maxLength: number): string {
+	if (text.length <= maxLength) {
+		return text;
+	}
+	return `${text.slice(0, Math.max(1, maxLength - 1))}…`;
+}