DMs to unreachable peers use store-and-forward instead of failing instantly (#1415)

* DMs to unreachable peers route through store-and-forward; drop stale reachability gates

Field-found: sendPrivateMessage pre-judged reachability and marked the
message failed without ever calling the router, so the retained outbox,
courier deposits, and bridge drops never ran — a DM composed after a
peer's reachability window lapsed was dead on arrival while an identical
one sent a minute earlier delivered. Messages now always route; a live
path earns "sent", everything else stays "sending" until the router
reports carried/delivered or expires it as failed.

A sweep for sibling gates found and fixed:
- startPrivateChat refused offline non-mutual favorites ("mutual favorite
  required for offline messaging") — store-and-forward only needs the
  recipient's noise key, so the gate and its string are gone.
- markPrivateMessagesAsRead skipped the whole receipt pass for peers
  without a stored Nostr key, starving mesh-connected non-favorites; the
  router picks the transport now (sentReadReceipts dedups the parallel
  PrivateChatManager path).
- DM/geoDM blocked notices and the unknown-group error posted to the
  active public timeline; they now land in the thread they're about via
  addLocalPrivateSystemMessage.
- Banned copy: literal "user" fallbacks in code become "anon" (the
  default-nickname convention), and es/fr/it/pt translations of four keys
  still saying usuario/utilisateur/utente/usuário now say person. Orphaned
  keys removed (system.dm.unreachable, content.delivery.reason.unreachable,
  system.chat.requires_favorite).

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

* Deflake BLEServiceCoreTests: longTimeout for positive waits

CI flaked on duplicatePacket_isDeduped: the first message landed after the
5s wait expired on a loaded runner (the test's later count==1 assertions
passed, proving late delivery, not lost delivery). All four positive waits
in the file now use TestConstants.longTimeout, which exists for exactly
this — waitUntil returns as soon as the condition holds, so passing runs
never pay the longer ceiling.

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

* Fix read-receipt test contamination; baseline Periphery noiseKey flake

Two CI failures, both environmental:

- markReadReceiptSent_returnsFalseOnSecondCall flaked because every test
  ChatViewModel shared one per-process read-receipts scratch suite; the
  lifecycle test persists the same "read-1" ID (a path the receipt-gate
  removal now reaches), and test order decided who saw whose state. Each
  instance now gets its own UUID-suffixed suite.

- Periphery intermittently misses the loadFromDisk read of
  PrekeyBundleStore.StoredBundle.noiseKey and fails --strict with a false
  "assign-only" finding (recurrence of a known flake). Its USR is
  baselined; an in-source periphery:ignore can't work because strict mode
  flags it as superfluous on runs where the indexer gets it right.

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

---------

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

bitchatTests/BLEServiceCoreTests.swift

@@ -32,7 +32,7 @@ struct BLEServiceCoreTests {
         ble._test_handlePacket(packet, fromPeerID: sender, signingPublicKey: signingKey)
         let receivedFirst = await TestHelpers.waitUntil(
             { delegate.publicMessagesSnapshot().count == 1 },
-            timeout: TestConstants.defaultTimeout
+            timeout: TestConstants.longTimeout
         )
         #expect(receivedFirst)
 
@@ -188,7 +188,7 @@ struct BLEServiceCoreTests {
 
         let rebound = await TestHelpers.waitUntil(
             { ble._test_centralBinding(centralUUID) == newPeerID },
-            timeout: TestConstants.defaultTimeout
+            timeout: TestConstants.longTimeout
         )
         #expect(rebound)
 
@@ -197,7 +197,7 @@ struct BLEServiceCoreTests {
                 let peerIDs = ble.currentPeerSnapshots().map(\.peerID)
                 return peerIDs.contains(newPeerID) && !peerIDs.contains(oldPeerID)
             },
-            timeout: TestConstants.defaultTimeout
+            timeout: TestConstants.longTimeout
         )
         #expect(retired)
     }
@@ -374,7 +374,7 @@ struct BLEServiceCoreTests {
 
         let reachedBudget = await TestHelpers.waitUntil(
             { outbound.count(ofType: .pong) >= budget },
-            timeout: TestConstants.defaultTimeout
+            timeout: TestConstants.longTimeout
         )
         #expect(reachedBudget)
         // Give any over-budget pong a chance to surface, then confirm the