Add party/raid group frames with edit-mode, group auras, indicators, range, and options

[Mapkov2]

Motivation

• Provide first-class Party and Raid group frames (separate from Blizzard frames) with configurable layout and preview in Edit Mode.
• Support group-specific aura handling including a simple designer/whitelist model so group frames can show grouped auras like bouquet lists.
• Integrate group frame behavior with existing Edit Mode tooling (movers, tickers, nudging, HUD) and add runtime features such as range fading, indicators, and private aura anchors.

Description

• Added a suite of core Group modules: Core/MSUF_GroupRoster.lua, Core/MSUF_GroupFrames.lua, Core/MSUF_GroupUpdate.lua, Core/MSUF_GroupAuras.lua, Core/MSUF_GroupIndicators.lua, Core/MSUF_GroupRange.lua, Core/MSUF_GroupHide.lua, and Core/MSUF_GroupPrivateAuras.lua to manage roster, pooling, layout, updates, auras, indicators, range fading, and Blizzard hiding.
• Extended Auras2 and options UI: added designer-related layout/override plumbing and a designer note in Options/MSUF_Options_Auras.lua, and a new group options panel Options/MSUF_Options_Group.lua that exposes party/raid configuration and a group-aura designer editor.
• Edit Mode integration: added EditMode2/MSUF_EM2_Group.lua popup, HUD button in MSUF_EM2_HUD.lua, mover/drag/nudge/ticker adjustments in MSUF_EM2_Movers.lua, MSUF_EM2_Ticker.lua, MSUF_EM2_Nudge.lua, and popup routing in MSUF_EM2_Popups.lua to support preview, dragging and positioning of group containers.
• Unit list and auras integration: updated Auras2/MSUF_A2_Units.lua to include party/raid unit lists, dynamic Units.GetAll() that appends active group units (including Edit Mode preview), and hooked CompactUnitFrame aura caching into group aura collection.
• Defaults and manifest: populated Foundation/MSUF_Defaults.lua with group DB defaults and added new files into MidnightSimpleUnitFrames.toc so group features are loaded.
• Misc: added preview/core plumbing for designer parsing, copying overrides between scopes, and helper utilities (icon layout, caching, designer lookup, event bucketing) across the new modules.

Testing

• No automated tests were run for this change.

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Codex Task