Feature/peer colors (#476)

* Feature: assign stable per-peer colors (non-self) across mesh/geohash/DM; keep self orange and mentions-to-me orange; cache colors

* Fix compile warnings: remove unused primaryColor in formatMessageAsText; remove unused CryptoKit import; mark peerColor/formatMessageAsText @MainActor to call main-actor helpers

* Fix: re-import CryptoKit for SHA256 usage in ChatViewModel

* Peer lists: apply same per-peer colors as chat (self orange); suffix uses lighter variant; geohash uses Nostr pubkey, mesh uses Noise key

* Fix warning: remove unused peerNicknames in MeshPeerList

* UI: add 'mention' action in message actions to prefill input with @nick#abcd and focus input

* UX: long-press a message to prefill @mention with sender's full nick#abcd and focus input

* UX: remove long-press mention; add context menu 'Copy message' that copies only the message body (no nick/timestamp)

* Geo teleported: robust tag detection (accept 't', 'teleport', and boolean-like values); mark self on send when tagging; should fix peer list icons

* Logs: add GeoTeleport diagnostics (incoming tags, self/peer marking, counts) to debug peer list dashed icon behavior

* Teleport persistence: store per-geohash teleported state in UserDefaults; initialize on startup; OR with location-derived status; sheet writes persisted flag on select/teleport

---------

Co-authored-by: jack <jackjackbits@users.noreply.github.com>

bitchat/Views/LocationChannelsSheet.swift

@@ -107,8 +107,8 @@ struct LocationChannelsSheet: View {
                     let subtitlePrefix = "#\(channel.geohash) • \(coverage)"
                     let highlight = viewModel.geohashParticipantCount(for: channel.geohash) > 0
                     channelRow(title: geohashTitleWithCount(for: channel), subtitlePrefix: subtitlePrefix, subtitleName: namePart, isSelected: isSelected(channel), titleBold: highlight) {
-                        // Selecting a suggested nearby channel is not a teleport
-                        manager.teleported = false
+                        // Selecting a suggested nearby channel is not a teleport. Persist this.
+                        manager.markTeleported(for: channel.geohash, false)
                         manager.select(ChannelID.location(channel))
                         isPresented = false
                     }
@@ -153,7 +153,7 @@ struct LocationChannelsSheet: View {
                         let level = levelForLength(gh.count)
                         let ch = GeohashChannel(level: level, geohash: gh)
                         // Mark this selection as a manual teleport
-                        manager.teleported = true
+                        manager.markTeleported(for: ch.geohash, true)
                         manager.select(ChannelID.location(ch))
                         isPresented = false
                     }) {