feat: change default port from 47822 to 37849 (v1.2.0)

47822 collided with ClaudeDo.Worker.exe on at least one user's machine.
37849 is high, registered to nobody, and avoids the prior conflict.
Both the Node port and the .NET port move together (still
wire-compatible). Defaults change only — if a user has a custom port
in mailbox.json, that stays.

README.md

@@ -73,7 +73,7 @@ Then drop this into your project's `.mcp.json`:
   "mcpServers": {
     "mailbox": {
       "type": "http",
-      "url": "http://127.0.0.1:47822/mcp"
+      "url": "http://127.0.0.1:37849/mcp"
     }
   }
 }
@@ -96,7 +96,7 @@ dotnet publish src/ClaudeMailbox -c Release -r win-x64 --self-contained -p:Publi
 Put the resulting `claude-mailbox.exe` on `PATH`. Windows-only `install-service` verbs (admin shell):
 
 ```
-claude-mailbox install-service [--port 47822] [--bind 127.0.0.1] [--db-path <path>]
+claude-mailbox install-service [--port 37849] [--bind 127.0.0.1] [--db-path <path>]
 claude-mailbox uninstall-service [--purge]
 ```
 
@@ -193,7 +193,7 @@ CLI flag   >   mailbox.json   >   built-in defaults
 
 `mailbox.json` is searched at `~/.claude-mailbox/mailbox.json` (per-user), and on Windows additionally at `%ProgramData%\ClaudeMailbox\mailbox.json` (machine-wide, written by `--service` install). Override with `--config <path>`.
 
-Defaults: port `47822`, bind `127.0.0.1`, database at `~/.claude-mailbox/mailbox.db`.
+Defaults: port `37849`, bind `127.0.0.1`, database at `~/.claude-mailbox/mailbox.db`.
 
 ---