feat(e2e): add Phase B scenarios with LLM-judged assertions and multi-project tests

Adds 6 new E2E scenarios in phase-b.test.ts covering multi-project grid
rendering, independent tab switching, status bar fleet state, and
LLM-judged agent response quality evaluation via Claude API.
Includes llm-judge.ts helper (raw Anthropic API fetch, haiku-4-5,
structured verdicts with confidence thresholds).

v2/tests/e2e/llm-judge.ts

@@ -0,0 +1,113 @@
+// LLM Judge — evaluates test outcomes via Claude API
+// Uses raw fetch (no SDK dep). Requires ANTHROPIC_API_KEY env var.
+// Skips gracefully when API key is absent.
+
+const API_URL = 'https://api.anthropic.com/v1/messages';
+const MODEL = 'claude-haiku-4-5-20251001'; // Fast + cheap for test judging
+const MAX_TOKENS = 512;
+
+export interface JudgeVerdict {
+  pass: boolean;
+  reasoning: string;
+  confidence: number; // 0-1
+}
+
+/**
+ * Check if the LLM judge is available (API key set).
+ */
+export function isJudgeAvailable(): boolean {
+  return !!process.env.ANTHROPIC_API_KEY;
+}
+
+/**
+ * Ask Claude to evaluate whether `actual` output satisfies `criteria`.
+ *
+ * Returns a structured verdict with pass/fail, reasoning, and confidence.
+ * Throws if API call fails (caller should catch and handle).
+ */
+export async function judge(
+  criteria: string,
+  actual: string,
+  context?: string,
+): Promise<JudgeVerdict> {
+  const apiKey = process.env.ANTHROPIC_API_KEY;
+  if (!apiKey) {
+    throw new Error('ANTHROPIC_API_KEY not set — LLM judge unavailable');
+  }
+
+  const systemPrompt = `You are a test assertion judge for a terminal emulator application called BTerminal.
+Your job is to evaluate whether actual output from the application meets the given criteria.
+Respond with EXACTLY this JSON format, nothing else:
+{"pass": true/false, "reasoning": "brief explanation", "confidence": 0.0-1.0}`;
+
+  const userPrompt = [
+    '## Criteria',
+    criteria,
+    '',
+    '## Actual Output',
+    actual,
+    ...(context ? ['', '## Additional Context', context] : []),
+    '',
+    'Does the actual output satisfy the criteria? Respond with JSON only.',
+  ].join('\n');
+
+  const response = await fetch(API_URL, {
+    method: 'POST',
+    headers: {
+      'Content-Type': 'application/json',
+      'x-api-key': apiKey,
+      'anthropic-version': '2023-06-01',
+    },
+    body: JSON.stringify({
+      model: MODEL,
+      max_tokens: MAX_TOKENS,
+      system: systemPrompt,
+      messages: [{ role: 'user', content: userPrompt }],
+    }),
+  });
+
+  if (!response.ok) {
+    const body = await response.text();
+    throw new Error(`Anthropic API error ${response.status}: ${body}`);
+  }
+
+  const data = await response.json();
+  const text = data.content?.[0]?.text ?? '';
+
+  // Extract JSON from response (may have markdown fences)
+  const jsonMatch = text.match(/\{[\s\S]*\}/);
+  if (!jsonMatch) {
+    throw new Error(`LLM judge returned non-JSON: ${text}`);
+  }
+
+  const verdict = JSON.parse(jsonMatch[0]) as JudgeVerdict;
+
+  // Validate structure
+  if (typeof verdict.pass !== 'boolean') {
+    throw new Error(`LLM judge returned invalid verdict: ${text}`);
+  }
+  verdict.confidence = Number(verdict.confidence) || 0;
+  verdict.reasoning = String(verdict.reasoning || '');
+
+  return verdict;
+}
+
+/**
+ * Convenience: judge with a minimum confidence threshold.
+ * Returns true only if pass=true AND confidence >= threshold.
+ */
+export async function assertWithJudge(
+  criteria: string,
+  actual: string,
+  options: { context?: string; minConfidence?: number } = {},
+): Promise<JudgeVerdict> {
+  const { context, minConfidence = 0.7 } = options;
+  const verdict = await judge(criteria, actual, context);
+
+  if (verdict.pass && verdict.confidence < minConfidence) {
+    verdict.pass = false;
+    verdict.reasoning += ` (confidence ${verdict.confidence} below threshold ${minConfidence})`;
+  }
+
+  return verdict;
+}