Make peer lists accessible and actionable; block mesh peers by stable identity (#1360)

* Make peer lists accessible and actionable; block by stable identity

Who you can reach — the app's most important fact — was encoded in
unlabeled 10pt icons with macOS-only tooltips, and the mesh list had no
actions (block/favorite/verify were slash-command-only).

- Both peer lists become real accessibility citizens: each row is one
  element announcing name, reachability, and favorite/unread/blocked
  state, with a button trait and custom actions for the gesture-only
  interactions. Neither file previously had a single accessibility
  modifier. Reachability icons gain tooltips reusing existing strings;
  teleported vs in-area pins are explained.
- Mesh rows gain the context menu the geohash list already had: direct
  message, favorite, show fingerprint, block/unblock. The fingerprint
  double-tap, previously shadowed by the single tap, is reordered so it
  fires.
- The DM header's offline state (previously EmptyView — absence of a
  glyph as the only signal) becomes a dimmed "offline" tag, and a
  geohash DM — always Nostr-routed — no longer mislabels itself
  "offline".
- App Info gains a SYMBOLS legend defining every glyph the lists and
  headers use; nothing defined them before.
- Mesh block/unblock now resolve by the peer's stable Noise identity
  instead of a `/block <displayName>` string, so the exact tapped row is
  affected and offline peers can be unblocked (with covering tests).

New strings are added source-language (en) only.

* Surface block/unblock feedback in the conversation where it was triggered

setMeshPeerBlocked silently returned when the peer's identity could not
be resolved (e.g. long-press-blocking an old public message from a
sender who left and was never a favorite), where the /block command
printed "cannot block X: not found or unable to verify identity" — post
that same message from the guard branch.

Both the failure and confirmation messages now route through
addCommandOutput instead of addSystemMessage, so blocking from inside a
private chat prints into that chat rather than invisibly into the
public timeline (same routing #1363 applied to command output).

The confirmation also reuses the /block wording ("blocked X. you will
no longer receive messages from them") for parity with the command.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* Remove dead accessibility label and unreachable /unblock fallback

The favorite button's .accessibilityLabel in MeshPeerList is
unreachable: the row-level .accessibilityElement(children: .ignore)
swallows child elements, and the row's custom accessibility action
already covers favoriting.

ConversationUIModel.unblock is only called from the mesh peer list with
a non-optional mesh peerID, so the "/unblock <name>" fallback branch
could never run — take PeerID directly and drop the branch.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

---------

Co-authored-by: jack <212554440+jackjackbits@users.noreply.github.com>
Co-authored-by: jack <jackjackbits@users.noreply.github.com>
Co-authored-by: Claude Fable 5 <noreply@anthropic.com>

bitchat/App/PrivateConversationModels.swift

@@ -232,7 +232,13 @@ final class PrivateConversationModel: ObservableObject {
         let headerPeerID = chatViewModel.getShortIDForNoiseKey(conversationPeerID)
         let peer = chatViewModel.getPeer(byID: headerPeerID)
         let displayName = resolveDisplayName(for: conversationPeerID, headerPeerID: headerPeerID, peer: peer)
-        let availability = resolveAvailability(for: headerPeerID, peer: peer)
+        // Geo DMs are always routed over Nostr (NIP-17); their nostr_ keys
+        // never resolve to a reachable mesh peer, so resolveAvailability would
+        // report .offline. Report .nostrAvailable so the header shows the
+        // globe instead of a misleading "offline" tag.
+        let availability = conversationPeerID.isGeoDM
+            ? .nostrAvailable
+            : resolveAvailability(for: headerPeerID, peer: peer)
         let encryptionStatus: EncryptionStatus? = conversationPeerID.isGeoDM
             ? nil
             : chatViewModel.getEncryptionStatus(for: headerPeerID)