fix(web): keep the viewer's conversation anchor across a Codeman restart

start() reassigns _claudeSessionId to `resumeSessionId || id` on every launch,
including the path that re-attaches to a mux session that outlived the restart.
A pane whose CLI had moved on via /clear therefore came back pointing the
response viewer at its pre-/clear transcript, and because Session.lastSubmitAt
lived only in memory, the history correlation had nothing to correct it with
until the user happened to type again — observed as hours of the eye showing a
conversation the pane had long since left.

Persist lastSubmitAt in SessionState, restore it in restoreMuxSessions(), and
flush it when the viewer adopts (a /clear emits no completion event, which is
the trigger that would otherwise have persisted it). Recovered panes now
re-derive their live conversation on the viewer's first poll.

Restoring a stale anchor is safe: the resolver already refuses a candidate
transcript older than the one the pane is currently on, which is the shape of a
respawn into a fresh conversation.

src/session.ts

@@ -499,6 +499,8 @@ export class Session extends EventEmitter {
       tmuxHistoryLimit?: number;
       /** Restored per-session attachment history. May include server-private external paths. */
       attachmentHistory?: SessionAttachmentHistoryItem[];
+      /** Restored wall-clock ms of the pane's last Enter (see `lastSubmitAt`). */
+      lastSubmitAt?: number;
       /** Remote execution metadata for sessions launched through SSH inside local tmux. */
       remote?: SessionRemote;
       /** Docker execution metadata for sessions launched inside a container via local tmux. */
@@ -525,6 +527,12 @@ export class Session extends EventEmitter {
     this._lastActivityAt = this.createdAt;
     // Set claudeSessionId — when resuming, the Claude conversation ID is the resumed one.
     this._claudeSessionId = config.resumeSessionId || this.id;
+    // Restored from state.json on boot recovery. start() resets _claudeSessionId
+    // to the launch id even when re-attaching to a mux session whose CLI has
+    // moved on (a `/clear` before the restart), so this anchor is what lets the
+    // response viewer re-derive the live conversation without waiting for the
+    // user to type again.
+    this._lastSubmitAt = config.lastSubmitAt ?? 0;
     this._mux = config.mux || null;
     this._useMux = config.useMux ?? (this._mux !== null && this._mux.isAvailable());
     this._muxSession = config.muxSession || null;
@@ -1119,6 +1127,7 @@ export class Session extends EventEmitter {
       // recovery can re-attach.
       respawnBlocked: this._respawnBlocked || undefined,
       attachmentHistory: this.attachmentHistory.length > 0 ? this.attachmentHistory : undefined,
+      lastSubmitAt: this._lastSubmitAt || undefined,
       // envOverrides intentionally NOT on the public SessionState type — they must not
       // leak into SSE / GET /api/sessions broadcasts (schema allows OPENCODE_*, which
       // can carry secrets). For disk persistence, session-manager calls

src/types/session.ts

@@ -459,6 +459,15 @@ export interface SessionState {
   effort?: EffortLevel;
   /** Sanitized per-session attachment history. */
   attachmentHistory?: SessionAttachmentHistoryItem[];
+  /**
+   * Wall-clock ms of this pane's last Enter (Session.lastSubmitAt). Persisted
+   * because it is the response-viewer's only anchor for re-deriving the pane's
+   * live conversation after a Codeman restart: `start()` resets
+   * `claudeSessionId` to the launch id even when re-attaching to a mux session
+   * whose CLI has since moved on via `/clear`, and the correlation cannot run
+   * again until the pane's own Enter is known.
+   */
+  lastSubmitAt?: number;
   /**
    * PTY-exit circuit breaker tripped — respawn blocked until an explicit restart
    * (COD-118). Runtime-only: never restored on boot (fresh server = fresh breaker).

src/web/routes/session-routes.ts

@@ -1228,6 +1228,11 @@ export function registerSessionRoutes(
     const activeId = await resolveActiveClaudeSessionIdFromHistory(session, projectsDir);
     if (activeId && activeId !== session.claudeSessionId) {
       session.adoptClaudeSessionId(activeId);
+      // Flush the Enter that vouched for this adoption to state.json. A `/clear`
+      // emits no completion event, so without this the anchor could still be
+      // unpersisted when the server restarts — and recovery would fall back to
+      // the launch conversation.
+      ctx.persistSessionState(session);
       // Docker sessions: keep the case's resume seed following the live conversation.
       if (session.docker) {
         void persistDockerCaseClaudeSessionId(CODEMAN_CONFIG_DIR, session.docker.containerName, activeId).catch(

src/web/server.ts

@@ -2464,6 +2464,10 @@ export class WebServer extends EventEmitter {
               envOverrides: savedEnvOverrides,
               effort: savedState?.effort,
               attachmentHistory: savedAttachmentHistory,
+              // The pane's last Enter. Without it the response viewer would show
+              // the launch conversation until the user types again, even though
+              // the re-attached CLI is on a post-`/clear` one.
+              lastSubmitAt: savedState?.lastSubmitAt,
               // Remote SSH metadata must round-trip on recovery: without it the
               // attach cwd falls back to the (nonexistent-locally) remote path and
               // respawn rebuilds a LOCAL command, breaking the pane and silently