feat(WARDEN-WP-0020): worker drafts real route answers in dry-run (T3 groundwork)

build_plans now computes the concrete routing answer for each route_answer action
in-process (reuses the catalog; read-only, no subprocess/network) and render_plans
shows it as a `draft:` line. The dry-run demonstrates the actual answer the executor
(T3) will send, not just an intent. RuleBrain stays the default; the llm-connect brain
(T2) is gated on llm-connect being operational + its /execute contract.

230 tests, lint clean. Live dry-run verified against the real inbox.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/warden/worker.py

@@ -149,9 +149,43 @@ class HubClient:
         return data if isinstance(data, list) else []
 
 
+def draft_route_answer(query: str) -> str:
+    """Compute the routing answer the worker would send for a query. Read-only.
+
+    Reuses the routing catalog in-process (no subprocess, no network) so the dry-run
+    shows the concrete answer the executor (T3) will send, not just an intent.
+    """
+    try:
+        from warden.routing.catalog import load_catalog
+
+        matches = load_catalog().find(query, limit=1)
+    except Exception:  # noqa: BLE001 — never let a lookup failure break planning
+        return ""
+    if not matches:
+        return f"No routing match for {query!r}; try `warden route list --all`."
+    e = matches[0]
+    role = "issue" if e.warden_executes else ("assist" if e.exec_capable else "route")
+    parts = [f"{e.id} — owner {e.owner_repo} ({e.subsystem}), warden role: {role}."]
+    if e.warden_executes and e.cert_command:
+        parts.append(f"Run: {e.cert_command}.")
+    elif e.has_native_exec:
+        parts.append(f"Primary: {e.exec_command}.")
+    elif e.exec_capable:
+        parts.append(f"Proxy: warden access {e.id} --fetch (as the caller).")
+    parts.append(f"See {e.wiki_ref}.")
+    return " ".join(parts)
+
+
 def build_plans(messages: List[dict], brain: Brain) -> List[WorkerPlan]:
-    """Plan every message and apply the guardrail pass. Pure — no execution."""
-    return [_guardrail(brain.plan(m), m) for m in messages]
+    """Plan every message, attach computed route answers, and apply the guardrail pass."""
+    plans: List[WorkerPlan] = []
+    for m in messages:
+        plan = brain.plan(m)
+        for a in plan.actions:
+            if a.kind == "route_answer" and "answer" not in a.payload:
+                a.payload["answer"] = draft_route_answer(a.payload.get("query", m.get("subject", "")))
+        plans.append(_guardrail(plan, m))
+    return plans
 
 
 def render_plans(plans: List[WorkerPlan]) -> str:
@@ -167,6 +201,8 @@ def render_plans(plans: List[WorkerPlan]) -> str:
         for a in p.actions:
             mark = "→" if a.risk == "safe" else "⚠"
             lines.append(f"    {mark} {a.kind}: {a.summary}")
+            if a.payload.get("answer"):
+                lines.append(f"       draft: {a.payload['answer']}")
             if a.risk == "escalate":
                 lines.append(f"       escalated: {a.reason}")
     return "\n".join(lines)