feat(terminals): reprise de conversation par cellule + fix ordre d'écriture

Permet de recharger la conversation CLI précédente de chaque cellule à la
réouverture du projet, de façon universelle (indépendant du modèle/CLI).

- profil AgentRuntime: bloc déclaratif optionnel `session { assignFlag, resumeFlag }`
- LeafCell: `conversationId` (persistant, distinct du SessionId PTY) + `agentWasRunning`
- runtime: SessionPlan (None/Assign/Resume) + composition pure des args
- LaunchAgent: décide Assign vs Resume, génère l'UUID, remonte l'id assigné
  (persistance par l'appelant via setCellConversation — découplage SRP)
- close: SnapshotRunningAgents fige `agentWasRunning` avant le kill-all
  (statut clot/en cours universel, sans parsing CLI)
- SessionInspector: port optionnel best-effort + adapter ClaudeTranscriptInspector
- popup de reprise par cellule (statut + sujet/tokens si dispo), intercalée
  avant le Resume auto, jamais sur le chemin reattach

fix(terminals): sérialise les écritures PTY (file FIFO par handle) — corrige
les caractères mélangés/accents dus au réordonnancement des invoke Tauri concurrents

fix(layout): l'opération `move` préservait mal les champs du leaf (perdait `agent`)

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

frontend/src/features/terminals/ResumeConversationPopup.tsx

@@ -0,0 +1,120 @@
+/**
+ * Resume-conversation popup (T7). Shown for an agent cell whose PTY session is
+ * dead but which carries a persisted `conversationId`, **before** the automatic
+ * Resume launch fires. It lets the user choose between resuming the previous CLI
+ * conversation or starting a fresh one.
+ *
+ * Pure presentation: it receives the status + best-effort details + the two
+ * action callbacks. It never calls a gateway / `invoke()` itself — the parent
+ * (`LayoutGrid`'s `LeafView`) wires it to the {@link AgentGateway} ports. The
+ * status ("en cours" / "clot") is derived **only** from `agentWasRunning` (the
+ * universal close-time flag), never from the inspector — a missing inspector
+ * just hides the enriched topic/token lines (degraded mode).
+ */
+
+import type { ConversationDetails } from "@/ports";
+
+interface ResumeConversationPopupProps {
+  /**
+   * Whether the agent process was running when the cell was last closed
+   * (`agentWasRunning`). `true` ⇒ "en cours"; `false`/absent ⇒ "clot". This is
+   * the universal status; it is NOT derived from the inspector.
+   */
+  agentWasRunning: boolean;
+  /**
+   * Best-effort enriched details (last topic + token indicator). `null` while
+   * loading; an empty object once loaded with no details available (degraded
+   * mode: only the status + the resume affordance are shown).
+   */
+  details: ConversationDetails | null;
+  /** Resume the previous conversation (keeps the conversation id ⇒ Resume). */
+  onResume: () => void;
+  /** Start a fresh conversation (clears the conversation id ⇒ Assign). */
+  onNewConversation: () => void;
+}
+
+export function ResumeConversationPopup({
+  agentWasRunning,
+  details,
+  onResume,
+  onNewConversation,
+}: ResumeConversationPopupProps) {
+  const statusLabel = agentWasRunning ? "en cours" : "clot";
+
+  return (
+    <div
+      data-testid="resume-conversation-popup"
+      role="dialog"
+      aria-label="Reprise de conversation"
+      style={{
+        position: "absolute",
+        inset: 0,
+        zIndex: 5,
+        display: "flex",
+        alignItems: "center",
+        justifyContent: "center",
+        background: "rgba(0, 0, 0, 0.55)",
+      }}
+    >
+      <div
+        style={{
+          minWidth: 260,
+          maxWidth: 360,
+          padding: "16px 18px",
+          background: "var(--color-surface, #1e1e1e)",
+          color: "var(--color-content, #e0e0e0)",
+          border: "1px solid var(--color-border, #3a3a3a)",
+          borderRadius: 6,
+          boxShadow: "0 8px 24px rgba(0, 0, 0, 0.5)",
+          fontSize: 13,
+        }}
+      >
+        <p style={{ margin: "0 0 8px", fontWeight: 600 }}>
+          Reprise de conversation
+        </p>
+
+        <p style={{ margin: "0 0 6px" }}>
+          Statut :{" "}
+          <span data-testid="resume-status">{statusLabel}</span>
+        </p>
+
+        {details?.lastTopic && (
+          <p style={{ margin: "0 0 6px" }} data-testid="resume-last-topic">
+            Dernier sujet : {details.lastTopic}
+          </p>
+        )}
+
+        {details?.tokenCount !== undefined && (
+          <p style={{ margin: "0 0 10px" }} data-testid="resume-token-count">
+            Tokens : {details.tokenCount}
+          </p>
+        )}
+
+        <div style={{ display: "flex", gap: 8, marginTop: 12 }}>
+          <button
+            type="button"
+            onClick={onResume}
+            style={{
+              flex: 1,
+              padding: "6px 10px",
+              cursor: "pointer",
+            }}
+          >
+            Reprendre la dernière conversation
+          </button>
+          <button
+            type="button"
+            onClick={onNewConversation}
+            style={{
+              flex: 1,
+              padding: "6px 10px",
+              cursor: "pointer",
+            }}
+          >
+            Nouvelle conversation
+          </button>
+        </div>
+      </div>
+    </div>
+  );
+}