[pedrozc90]

Restructures the addon into small focused modules and removes dead code, with no intended change to in-game behavior or visuals.

Changes

• Structure: split Filger.lua into core/button.lua (button widget), core/element.lua (layout + spawn) and elements/cooldowns.lua; family auras moved to elements/[Family]/auras.lua.
• Spawn: dispatch on explicit element type instead of filter/groups; auras and cooldowns share button acquisition and render path.
• Cooldowns: casted/active state is created per element instead of on the prototype.
• Config: aura frame layout defined once in config.lua; unused API, config fields and commented code removed.
• Libraries: removed unused LibClassicDurations and CallbackHandler-1.0.
• ElvUI/Tukui: button backdrop deferred to ElvUI; Classic dispel borders colored under Tukui/ElvUI.
• Fix: removed load-time print from data files that tainted chat history (fixes Load-time print in data/Standard/spells.lua taints chat history #6).
• Normalized line endings to LF; documented load order in Filger.toc.

Testing

• make check (luacheck) passes.
• Verify in-game on Retail and Classic clients: auras and cooldowns display, with and without ElvUI/Tukui.