docs: reconcile protocol docstrings with implementation

- BitchatProtocol.swift: stop advertising "timing obfuscation prevents
  traffic analysis" — what exists is randomized relay jitter
  (RelayController, 10-220 ms) and PKCS#7-style padding to
  256/512/1024/2048-byte blocks (MessagePadding); there is no cover
  traffic or per-message timing obfuscation. Also update the stale
  Message Types list (Delivery/Read are Noise payloads, no Version
  negotiation type; add CourierEnvelope/RequestSync/FileTransfer).
- MessageType.swift: header said "6 essential" types; the enum has 9
  cases.

WHITEPAPER.md needed no changes: the #1372 rewrite already replaced the
old Bloom-filter and MessageRetryService claims, and its numbers
(dedup 1000/5min, jitter, outbox 100/peer 24h 8 attempts, courier
16 KiB/24h/40-20-5-2 quotas, spray 4/8, gossip 1000/15s/6h) all match
the code.

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

bitchat/Protocols/BitchatProtocol.swift

@@ -18,7 +18,7 @@
 /// - Efficient binary message encoding
 /// - Message fragmentation for large payloads
 /// - TTL-based routing for mesh networks
-/// - Privacy features like padding and timing obfuscation
+/// - Privacy features: message padding and randomized relay jitter
 /// - Integration points for end-to-end encryption
 ///
 /// ## Protocol Design
@@ -38,18 +38,20 @@
 /// 7. **Decoding**: Binary data parsed back to message objects
 ///
 /// ## Security Considerations
-/// - Message padding obscures actual content length
-/// - Timing obfuscation prevents traffic analysis
+/// - Message padding (to 256/512/1024/2048-byte blocks) obscures actual content length
+/// - Randomized relay jitter reduces the traffic-analysis signal; there is no
+///   cover traffic or per-message timing obfuscation
 /// - Integration with Noise Protocol for E2E encryption
 /// - No persistent identifiers in protocol headers
 ///
 /// ## Message Types
 /// - **Announce/Leave**: Peer presence notifications
-/// - **Message**: User chat messages (broadcast or directed)
+/// - **Message**: Public chat messages
 /// - **Fragment**: Multi-part message handling
-/// - **Delivery/Read**: Message acknowledgments
-/// - **Noise**: Encrypted channel establishment
-/// - **Version**: Protocol version negotiation
+/// - **NoiseHandshake/NoiseEncrypted**: Encrypted channel establishment and
+///   all private payloads (messages, delivery acks, read receipts)
+/// - **CourierEnvelope**: Sealed store-and-forward mail
+/// - **RequestSync/FileTransfer**: Gossip history sync and media transfer
 ///
 /// ## Future Extensions
 /// The protocol is designed to be extensible:

localPackages/BitFoundation/Sources/BitFoundation/MessageType.swift

@@ -7,7 +7,7 @@
 //
 
 /// Simplified BitChat protocol message types.
-/// Reduced from 24 types to just 6 essential ones.
+/// Consolidated from the original 24 wire types down to the 9 cases below.
 /// All private communication metadata (receipts, status) is embedded in noiseEncrypted payloads.
 public enum MessageType: UInt8 {
     // Public messages (unencrypted)