Wire AI features to Claude (claude-sonnet-5); fix key detection + retired model

The Anthropic path could never activate: it gated on
`not ANTHROPIC_API_KEY.startswith("sk-ant-")`, but real Anthropic keys start
with `sk-ant-`, so any real key was treated as a placeholder and every request
fell back to mock. It also targeted the retired `claude-3-haiku-20240307`.

- ai_translator.py: add `_real_key()` placeholder detection (rejects `sk-ant-...`,
  `changeme`, `your-`, etc. — accepts real secrets), centralize provider gating
  in `_ai_enabled()`, and point all three AI features (finding translation,
  security coach, attack-path narrative) at `claude-sonnet-5` with thinking
  disabled for fast structured output. OpenAI kept as a secondary provider.
- config.py / .env.example: default AI_PROVIDER to anthropic.

Mock mode still works with no key configured; dropping in a real
ANTHROPIC_API_KEY now actually enables live Claude.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

backend/app/services/ai_translator.py

@@ -12,7 +12,51 @@ import logging
 
 logger = logging.getLogger(__name__)
 
-TRANSLATION_SYSTEM_PROMPT = """You are TrustOS, an AI cyber resilience advisor. 
+# Current Claude model for all AI features. Sonnet 5 is a strong fit for this
+# high-volume translation/classification work — near-Opus quality at lower cost.
+CLAUDE_MODEL = "claude-sonnet-5"
+OPENAI_MODEL = "gpt-4o-mini"
+
+_PLACEHOLDER_MARKERS = ("...", "changeme", "your-", "replace")
+
+
+def _real_key(value: Optional[str]) -> Optional[str]:
+    """Return the key only if it looks like a real secret (not a placeholder).
+
+    The .env ships with placeholders like ``sk-ant-...`` and ``sk-...``; a real
+    key must be present and contain none of the placeholder markers. (The old
+    code checked ``startswith("sk-ant-")``, which matches *real* Anthropic keys
+    too, so it could never use one.)
+    """
+    if not value:
+        return None
+    lowered = value.lower()
+    if any(marker in lowered for marker in _PLACEHOLDER_MARKERS):
+        return None
+    return value
+
+
+def _anthropic_key():
+    from app.core.config import settings
+    return _real_key(settings.ANTHROPIC_API_KEY)
+
+
+def _openai_key():
+    from app.core.config import settings
+    return _real_key(settings.OPENAI_API_KEY)
+
+
+def _ai_enabled() -> bool:
+    """True when a real API key is configured for the active provider."""
+    from app.core.config import settings
+    if settings.AI_PROVIDER == "anthropic":
+        return _anthropic_key() is not None
+    if settings.AI_PROVIDER == "openai":
+        return _openai_key() is not None
+    return False
+
+
+TRANSLATION_SYSTEM_PROMPT = """You are TrustOS, an AI cyber resilience advisor.
 Your role is to translate technical cybersecurity findings into clear, plain-English 
 business impact statements for executive and non-technical audiences.
 
@@ -37,11 +81,24 @@ async def _call_llm(prompt: str) -> Optional[str]:
     """Call the configured LLM provider. Returns raw text response."""
     from app.core.config import settings
     try:
-        if settings.AI_PROVIDER == "openai" and settings.OPENAI_API_KEY and not settings.OPENAI_API_KEY.startswith("sk-..."):
+        anthropic_key = _anthropic_key()
+        openai_key = _openai_key()
+        if settings.AI_PROVIDER == "anthropic" and anthropic_key:
+            from anthropic import AsyncAnthropic
+            client = AsyncAnthropic(api_key=anthropic_key)
+            resp = await client.messages.create(
+                model=CLAUDE_MODEL,
+                max_tokens=1024,
+                thinking={"type": "disabled"},  # fast, structured JSON output
+                system=TRANSLATION_SYSTEM_PROMPT,
+                messages=[{"role": "user", "content": prompt}],
+            )
+            return resp.content[0].text
+        elif settings.AI_PROVIDER == "openai" and openai_key:
             from openai import AsyncOpenAI
-            client = AsyncOpenAI(api_key=settings.OPENAI_API_KEY)
+            client = AsyncOpenAI(api_key=openai_key)
             resp = await client.chat.completions.create(
-                model="gpt-4o-mini",
+                model=OPENAI_MODEL,
                 messages=[
                     {"role": "system", "content": TRANSLATION_SYSTEM_PROMPT},
                     {"role": "user", "content": prompt}
@@ -50,16 +107,6 @@ async def _call_llm(prompt: str) -> Optional[str]:
                 response_format={"type": "json_object"},
             )
             return resp.choices[0].message.content
-        elif settings.AI_PROVIDER == "anthropic" and settings.ANTHROPIC_API_KEY and not settings.ANTHROPIC_API_KEY.startswith("sk-ant-"):
-            from anthropic import AsyncAnthropic
-            client = AsyncAnthropic(api_key=settings.ANTHROPIC_API_KEY)
-            resp = await client.messages.create(
-                model="claude-3-haiku-20240307",
-                max_tokens=1024,
-                system=TRANSLATION_SYSTEM_PROMPT,
-                messages=[{"role": "user", "content": prompt}],
-            )
-            return resp.content[0].text
         else:
             logger.info("No valid AI provider configured — using mock translation")
             return _generate_mock_translation(prompt)
@@ -137,11 +184,24 @@ Answer in 2-4 sentences. Be specific to this finding. Use plain English."""
 
     from app.core.config import settings
     try:
-        if settings.AI_PROVIDER == "openai" and settings.OPENAI_API_KEY and not settings.OPENAI_API_KEY.startswith("sk-..."):
+        anthropic_key = _anthropic_key()
+        openai_key = _openai_key()
+        if settings.AI_PROVIDER == "anthropic" and anthropic_key:
+            from anthropic import AsyncAnthropic
+            client = AsyncAnthropic(api_key=anthropic_key)
+            resp = await client.messages.create(
+                model=CLAUDE_MODEL,
+                max_tokens=256,
+                thinking={"type": "disabled"},
+                system=system,
+                messages=[{"role": "user", "content": prompt}],
+            )
+            return resp.content[0].text
+        elif settings.AI_PROVIDER == "openai" and openai_key:
             from openai import AsyncOpenAI
-            client = AsyncOpenAI(api_key=settings.OPENAI_API_KEY)
+            client = AsyncOpenAI(api_key=openai_key)
             resp = await client.chat.completions.create(
-                model="gpt-4o-mini",
+                model=OPENAI_MODEL,
                 messages=[
                     {"role": "system", "content": system},
                     {"role": "user", "content": prompt}
@@ -149,16 +209,6 @@ Answer in 2-4 sentences. Be specific to this finding. Use plain English."""
                 temperature=0.5,
             )
             return resp.choices[0].message.content
-        elif settings.AI_PROVIDER == "anthropic" and settings.ANTHROPIC_API_KEY and not settings.ANTHROPIC_API_KEY.startswith("sk-ant-"):
-            from anthropic import AsyncAnthropic
-            client = AsyncAnthropic(api_key=settings.ANTHROPIC_API_KEY)
-            resp = await client.messages.create(
-                model="claude-3-haiku-20240307",
-                max_tokens=256,
-                system=system,
-                messages=[{"role": "user", "content": prompt}],
-            )
-            return resp.content[0].text
     except Exception as e:
         logger.error(f"AI coach call failed: {e}")
 
@@ -185,13 +235,7 @@ async def generate_attack_path_narrative(finding_id: str):
         if not finding:
             return
 
-        from app.core.config import settings
-        use_mock = not (
-            (settings.AI_PROVIDER == "openai" and settings.OPENAI_API_KEY and not settings.OPENAI_API_KEY.startswith("sk-...")) or
-            (settings.AI_PROVIDER == "anthropic" and settings.ANTHROPIC_API_KEY and not settings.ANTHROPIC_API_KEY.startswith("sk-ant-"))
-        )
-
-        if use_mock:
+        if not _ai_enabled():
             raw = _generate_mock_attack_path(finding)
         else:
             prompt = f"""Create an attack path for this vulnerability: