fix(oracle-r4): honest agent framing + 3 new QA gates

Oracle round-7 items 1, 4, 6:
- Agent welcome + sidebar copy clearly say 'deterministic command
  router' with 'EA2-backed text memory' (keyword recall). LLM adapter
  described as 'separate component, off by default'. No more 'natural
  language LLM on the roadmap' overclaim.
- 3 new full_dogfood gates:
  * memory_vault_remember_acks (proves vault write)
  * memory_vault_recall_returns_match (proves vault read by content)
  * llm_unconfigured_falls_back_gracefully (proves agent never crashes
    when LLM proxy isn't wired - the current state)
  * chat_sidebar_shows_previews_and_timestamps (proves chat polish
    elements render)

src/scenes/Agent.tsx

@@ -28,7 +28,7 @@ export default function Agent() {
       role: "agent",
       ok: true,
       text:
-        `Hi ${userEmail.split("@")[0]}. I'm the FlowMaster Command Assistant. I understand a fixed set of commands today and run them against the real EA2 backend — navigate, list processes, start a process, message a teammate, open the Studio. A natural-language LLM and per-tenant memory are on the roadmap.`,
+        `Hi ${userEmail.split("@")[0]}. I'm the FlowMaster Command Assistant. I understand a fixed set of commands and run them against EA2 — navigate, list processes, start a process, message a teammate, remember a note, recall notes. Memory is text-only with keyword recall; an LLM backend is a separate component, off by default.`,
     },
   ]);
   const [draft, setDraft] = useState("");
@@ -65,7 +65,7 @@ export default function Agent() {
         <header className="agent-side-head">
           <div className="mc-hero-eyebrow"><Bot size={12} /> FlowMaster Command Assistant</div>
           <h2 className="mc-hero-title">Tell the cockpit what to do</h2>
-          <p className="agent-side-sub">Deterministic command router today. An LLM-backed agent with per-tenant memory is the next milestone.</p>
+          <p className="agent-side-sub">Deterministic command router with EA2-backed text memory. The LLM adapter ships separately when a provider key is configured.</p>
         </header>
         <div className="agent-tool-list">
           <div className="agent-tool-label">CAPABILITIES</div>