v0.3.6: Network indicator, tab badges, message read tracking, UI cleanup

UI:
- Network indicator dot (black/red/yellow/green) + capability labels (Public, Server)
- Tab badges: Feed (new posts), My Posts (new engagement), People (online), Messages (unread)
- Stats bar removed — contextual counts in tab labels
- Message thread popup variable scoping fix

Message read tracking:
- mark_conversation_read on popover open, close, and message send
- Prevents re-notification of already-seen messages after app restart

Network:
- Added has_public_v6(), has_upnp() getters on Network
- NetworkSummaryDto includes hasPublicV6, hasPublicV4, hasUpnp

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

website/design.html

@@ -44,7 +44,7 @@
             <p>This is the canonical technical reference for ItsGoin. It describes the vision, the architecture, and the current state of every subsystem &mdash; with full implementation detail. This document is versioned; each update records what changed.</p>
             <div class="card" style="margin-top: 1rem;">
                 <strong style="font-size: 0.85rem; text-transform: uppercase; letter-spacing: 0.05em;">Changelog</strong>
-                <p style="margin-top: 0.5rem;"><strong>v0.3.6</strong> (2026-03-20): Active CDN replication &mdash; all devices proactively replicate recent posts to peers (desktops &gt; anchors &gt; phones priority). ReplicationRequest/Response (0xE1/0xE2). Device roles (Intermittent/Available/Persistent) advertised in InitialExchange. Bandwidth budgets: replication (pull to cache) + delivery (serve requests), hourly auto-reset. Cache management: 1GB default, configurable, eviction cycle activated with share-link priority boost. Engagement distribution fix &mdash; BlobHeader JSON rebuilt after diff ops. Tombstone system &mdash; deleted reactions/comments tombstoned, propagate via pull sync. Persistent notifications via seen_engagement/seen_messages tables. DOS hardening: fan-out cap (10), prefetch cap (20), downstream registration cap (50), delivery budget enforcement. Pull preference reordered: non-anchors first.</p>
+                <p style="margin-top: 0.5rem;"><strong>v0.3.6</strong> (2026-03-20): Active CDN replication &mdash; all devices proactively replicate recent posts to peers (desktops &gt; anchors &gt; phones priority). ReplicationRequest/Response (0xE1/0xE2). Device roles (Intermittent/Available/Persistent) advertised in InitialExchange. Bandwidth budgets: replication (pull to cache) + delivery (serve requests), hourly auto-reset, phones 100MB/1GB, desktops 200MB/2GB, anchors 200MB/1GB. Cache management: 1GB default, configurable, eviction cycle activated with share-link priority boost. Engagement distribution fix &mdash; BlobHeader JSON rebuilt after diff ops. Tombstone system &mdash; deleted reactions/comments tombstoned, propagate via pull sync. Persistent notifications via seen_engagement/seen_messages tables. DOS hardening: fan-out cap (10), prefetch cap (20), downstream registration cap (50), delivery budget enforcement. Pull preference reordered: non-anchors first. Network indicator &mdash; header dot (black/red/yellow/green) + capability labels. Tab badges &mdash; contextual counts (new posts, engagement, online, unread). Message read tracking on open/close/send. Stats bar removed.</p>
                 <p><strong>v0.3.5</strong> (2026-03-20): Private blob encryption &mdash; attachments on encrypted posts (Friends/Circle/Direct) now encrypted with same CEK as post text; public blobs unchanged; CID on ciphertext. Blob prefetch on sync &mdash; attachments eagerly fetched after post pull for offline availability. Crypto refactoring &mdash; extracted reusable primitives (encrypt/decrypt_bytes_with_cek, unwrap_cek_for_recipient, unwrap_group_cek). Intent-based post filtering &mdash; feed/myposts/messages filter on intentKind instead of encryption state. Blob decryption API (get_blob_for_post). Download filename sanitization. Encrypted receipt &amp; comment slots &mdash; private posts carry noise-prefilled encrypted slots in BlobHeader for delivery/read/react receipts and private comments; CDN-propagated as opaque bytes; slot key derived from post CEK; 3 new BlobHeaderDiffOps (WriteReceiptSlot, WriteCommentSlot, AddCommentSlots). Message UI &mdash; DM delivery indicators (checkmark/double/blue/emoji), auto-seen on view, react button on messages.</p>
                 <p><strong>v0.3.4</strong> (2026-03-18): Comment edit &amp; delete with trust-based propagation. Native notifications via Tauri plugin (messages, posts, reactions, comments). Forward-compatible BlobHeaderDiffOp::Unknown variant. Following Online/Offline lightbox. Comment threading scoping fix. Dropdown text legibility fix. Mobile hamburger nav for website.</p>
                 <p><strong>v0.3.3</strong> (2026-03-16): Connection rate limiting &mdash; incoming auth failures rate-limited per source IP (3 attempts, exponential backoff to ~256s). Schema versioning &mdash; PRAGMA user_version tracks DB version with migration framework. N2/N3 freshness &mdash; TTL 7d&rarr;5h, full N1/N2 re-broadcast every 4h, startup sweep clears stale entries. Bootstrap isolation recovery &mdash; 24h check verifies bootstrap is in N1/N2/N3, reconnects + sticky N1 advertisement if absent. IPv6 HTTP address fix &mdash; nodes advertise actual public IPv6 (not 0.0.0.0) for share link redirects. Upstream tracking &mdash; post_upstream table records post source for engagement diff routing toward author. Video preload fix &mdash; share links and in-app videos use preload=auto. Following Online/Offline split. DM filter from My Posts. Any-type file attachments with download prompt + trust warning. Image lightbox. Audio player.</p>