Focus Tank Button

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CHANGELOG SUMMARY
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v1.2

 - Updated TOC to include Mists of Pandaria Classic version 5.5.3
 - Fixed an issue where the Focus Tank button would not appear on newly
   created characters.
 - Corrected position saving logic to store and restore full SetPoint
   data, preventing invalid or off-screen placement.
 - Implemented per-character position and visibility handling while
   keeping indicator, blink settings account-wide.
 - Added safe fallback positioning to ensure a default location is used
   if saved data is missing or invalid.
 - Improved initialization flow to respect Blizzard UI load order and
   ensure reliable button visibility after login.
 - Blinking is now enabled by default for new installs (blinkEnabled = true).
 - Indicator behavior is fully gated by user settings (indicator + blink toggles).
 - Hardened indicator logic to avoid errors during login, logout, and combat transitions.
 - Resolved critical OnUpdate handler bug created by code changes that caused Lua error spam and client instability.
 - Corrected the OnUpdate function signature to safely handle elapsed time.
 - Improved safety guards around OnUpdate registration and removal.
 - Prevented runaway blinking logic that could persist after disabling the indicator.
 - Ensured indicator alpha always resets correctly when blinking stops.
 - Edited chat usage text and removed debug option