chore(release): 0.16.0

[Aaronontheweb]

Release 0.16.0 — 2026-04-27

This PR prepares the 0.16.0 release: updates RELEASE_NOTES.md with the new changelog section and bumps VersionPrefix in Directory.Build.props to 0.16.0.

Highlights

Discord session continuity — Discord thread sessions now rehydrate correctly after daemon restart without requiring an @mention, matching Slack's existing behavior. Approval buttons are also cleared in-place after a decision is made.

Public audience hardening — Public sessions are fully amnesic, see a filtered tool index, and no longer leak root path hints in file-access denials. System prompt rebuilds on first inbound turn once audience is resolved.

Reminder lifecycle improvements — Recurring reminders now support an ExpiresIn parameter for automatic expiration, include self-cancellation guidance, and the delivery observation timeout is aligned with the full execution window (300s).

Init wizard overhaul — A unified channel picker step replaces sequential Slack/Discord steps, Discord channel IDs resolve to human-readable names, and the AllowedUserIds field is now an explicit allow/restrict choice to enforce default-deny security posture.

Container hardening — Daemon.DisableSelfUpdate is set automatically in the official Docker image; libsodium23 is added to fix NSec signature verification in Ubuntu 24.04 containers.

Attachment streaming — Attachment downloads from Slack and Discord now stream directly to disk instead of buffering in managed heap memory.

Strict serialization — System.Object JSON fallback is disabled; unregistered types fail loudly with SerializationException.

Configuration-driven stats — netclaw stats and netclaw status only show panels for enabled channels.

Commits included

• feat(reminders): expiration, self-cancellation, and delivery timeout fix (feat(reminders): expiration, self-cancellation, and delivery timeout fix #752)
• feat(security): public audience security hardening (feat(security): public audience security hardening #758)
• feat(tui): resolve Discord channel IDs to human-readable names (feat(tui): resolve Discord channel IDs to human-readable names (#743) #762)
• feat(wizard): unified channel picker step for init wizard (feat(wizard): unified channel picker step for init wizard #763)
• fix(tui): remove dead OwnerIdentity sub-step from Slack wizard (fix(tui): remove dead OwnerIdentity sub-step from Slack wizard #764)
• feat(discord): clear approval buttons after decision (feat(discord): clear approval buttons after decision #768)
• feat(channels): stream attachment downloads to disk instead of buffering in memory (feat(channels): stream attachment downloads to disk instead of buffering in memory #770)
• feat(stats): configuration-driven channel statistics (feat(stats): configuration-driven channel statistics (#773) #774)
• feat(tui): make AllowedUserIds an explicit allow/restrict choice (feat(tui): make AllowedUserIds an explicit allow/restrict choice (#760) #778)
• feat(serialization): disable System.Object serialization fallback (feat(serialization): disable System.Object serialization fallback #777)
• feat(docker): block self-update in containers, harden NSec (feat(docker): block self-update in containers, harden NSec #776)
• fix(discord): rehydrate thread sessions after daemon restart without requiring mention (fix(discord): rehydrate thread sessions after daemon restart #779)