fix: remote session discovery gating and empty replay on remote open (0.3.1)

[william0wang]

Summary

Two remote-access fixes found while debugging live hub state, plus the 0.3.1 release bump.

Fix 1 — discovery no longer lists never-used sessions (cd1b58c)

Root cause: an editor restart auto-resumes its stored session/new placeholder, which materializes an empty backend session. The bridge pushed every registered session to the hub, so remote clients listed (and opened) conversations that never happened.

Fix: session summaries carry a hasActivity flag, set only by real interaction — a completed prompt turn (any outcome), a session/load with replayable history, or an adopted stored title. sessionsPayload filters on it. The hub replaces the session list on every register, so entries appear/disappear within one heartbeat (~10s).

Fix 2 — old conversations opened empty on remote clients (40b7209)

Root cause: the backend subprocess only answers session/messages for sessions it has loaded via session/create/session/resume. The bridge's alreadyLive check trusted the in-memory id mapping, which can exist without the session ever being loaded into the current backend (re-registered from the durable store, or left behind by a failed resume) — so session/load skipped the resume RPC and replayed nothing. fetchMessages also swallowed session/messages errors as empty, masking it. Verified live: the affected session returned totalMessages: 0 by ACP id but 352 messages / 52 turns after a forced resume — data intact, purely a bridge-side skip.

Fix: explicit backendLoadedSessions tracking — stamped only after a successful create/resume RPC; resolveResumeTarget skips the resume RPC only for verified sessions, otherwise re-issues it. fetchMessages now warns on errors instead of silently replaying empty.

Testing

• 578 tests pass, typecheck/lint/build clean
• New coverage: discovery payload gating (register-only vs marked vs titled), never-used placeholder stays hidden, load-with-history becomes discoverable, resume re-issue for never-loaded mappings, resume skip for verified-loaded sessions, placeholder materialization stamps the session

Docs

REMOTE-CLIENTS (sessions list semantics), TROUBLESHOOTING (empty-conversation-on-remote section), CHANGELOG 0.3.1.