Fix MailMailButton nil errors and bump to 1.4.8

- Fix MailMailButton nil errors in SendMailFrame_CanSend and sendmail_clear
- Keep a safe reference to the original Send Mail button
- Add fallback handling for MailSubjectEditBox
- Improve compatibility with UI/mailbox modifications
- Update version to 1.4.8
- Update README and audit documentation

README.md

@@ -76,7 +76,7 @@ When enabled, TurtleMail records sent and received mail information in its dedic
 
 ## 🔧 Turtle WoW compatibility
 
-Version **1.4.7** extends the compatibility and safety layer for Turtle WoW 1.18.x environments.
+Version **1.4.8** extends the compatibility and safety layer for Turtle WoW 1.18.x environments.
 
 The compatibility work is isolated in `TurtleMailFix.lua` so the original TurtleMail code remains easier to compare with upstream versions.
 
@@ -95,6 +95,7 @@ The compatibility work is isolated in `TurtleMailFix.lua` so the original Turtle
 - Fixed calendar tooltip nil/stale-value cases.
 - Rebound the safer `OnUpdate` handler correctly after loading the compatibility layer.
 - Prevented the send queue from remaining stuck when an attachment becomes unavailable during sending.
+- Fixed `MailMailButton` nil crashes while enabling/disabling or clearing the send form, and hardened the paired subject edit-box reference.
 
 The complete technical audit is available in [`AUDIT.md`](AUDIT.md).
 
@@ -129,11 +130,11 @@ TurtleMail includes localization support for:
 
 Current stable version:
 
-**1.4.7**
+**1.4.8**
 
 Based on upstream **TurtleMail 1.4.5**.
 
-Version 1.4.7 has been validated in-game on Turtle WoW 1.18.x without Lua errors in the tested setup.
+Version 1.4.8 adds an additional safeguard for the legacy send-button proxy used by TurtleMail. The earlier compatibility fixes remain unchanged.
 
 ## 🖼️ Screenshots