Fix slash-command suggestions that insert commands the processor rejects (#1354)

The autocomplete panel is the only in-app surface for discovering slash
commands, but several suggestions do not match what CommandProcessor
accepts, so tapping them inserts a command that returns "unknown
command":

- CommandInfo suggests /dm, /favorite, /unfavorite, but the processor
  only handles /m, /msg, /fav, /unfav. Aliases are aligned to the
  accepted spellings (msg, fav, unfav).
- Favorites are suggested only in geohash contexts (isGeoPublic ||
  isGeoDM) — exactly where the processor rejects them ("favorites are
  only for mesh peers"). The gating is inverted so they appear in mesh,
  where they work.

Also, small related fixes to the discovery surface:
- /help is now handled (the ChatViewModel command docstring already
  claimed it existed); it prints a local system line listing the valid
  commands, and the unknown-command error points at it.
- The suggestion panel keeps the matched command's usage row (e.g.
  "/msg <nickname>") visible while arguments are typed, instead of
  vanishing at the first space; in that mode the row is informational
  and no longer overwrites the draft on tap.

New string is added source-language (en) only. The CommandInfo contract
test is updated to the corrected metadata.

bitchat/Models/CommandInfo.swift

@@ -11,33 +11,38 @@ import Foundation
 // MARK: - CommandInfo Enum
 
 enum CommandInfo: String, Identifiable {
+    // Raw values must match the aliases CommandProcessor actually accepts —
+    // the suggestion panel is the app's only command-discovery surface, and
+    // suggesting a spelling the processor rejects teaches users dead ends.
     case block
     case clear
+    case help
     case hug
-    case message = "dm"
+    case message = "msg"
     case slap
     case unblock
     case who
-    case favorite
-    case unfavorite
-    
+    case favorite = "fav"
+    case unfavorite = "unfav"
+
     var id: String { rawValue }
-    
+
     var alias: String { "/" + rawValue }
-    
+
     var placeholder: String? {
         switch self {
         case .block, .hug, .message, .slap, .unblock, .favorite, .unfavorite:
             return "<" + String(localized: "content.input.nickname_placeholder") + ">"
-        case .clear, .who:
+        case .clear, .help, .who:
             return nil
         }
     }
-    
+
     var description: String {
         switch self {
         case .block:        String(localized: "content.commands.block")
         case .clear:        String(localized: "content.commands.clear")
+        case .help:         String(localized: "content.commands.help")
         case .hug:          String(localized: "content.commands.hug")
         case .message:      String(localized: "content.commands.message")
         case .slap:         String(localized: "content.commands.slap")
@@ -47,12 +52,14 @@ enum CommandInfo: String, Identifiable {
         case .unfavorite:   String(localized: "content.commands.unfavorite")
         }
     }
-    
+
     static func all(isGeoPublic: Bool, isGeoDM: Bool) -> [CommandInfo] {
-        let baseCommands: [CommandInfo] = [.block, .unblock, .clear, .hug, .message, .slap, .who]
+        let baseCommands: [CommandInfo] = [.block, .unblock, .clear, .help, .hug, .message, .slap, .who]
+        // The processor rejects favorites in geohash contexts, so only
+        // suggest them where they actually work: mesh.
         if isGeoPublic || isGeoDM {
-            return baseCommands + [.favorite, .unfavorite]
+            return baseCommands
         }
-        return baseCommands
+        return baseCommands + [.favorite, .unfavorite]
     }
 }