feat: add DungeonNotes addon and shared minimap button via LibDBIcon

[loicngr]

• New ZaeUI_DungeonNotes addon: per-character dungeon and raid notes with a floating editor, instance-entry notification, instance browser, profile export/import and /zdn slash command
• ZaeUI_Shared: vendor LibStub, CallbackHandler-1.0, LibDataBroker-1.1 and LibDBIcon-1.0 in Libs/ for standard minimap button integration
• Shared minimap button: left-click opens ZaeUI settings, drag to reposition, right-click opens a context menu built via a new ZaeUI_Shared.registerMenuAction API; DungeonNotes registers the first action ("Open Dungeon Notes")
• Promote the ZaeUI parent Settings category to host global preferences (minimap button toggle + hint)
• Set IconTexture to a new ZaeUI logo on every addon TOC so the in-game AddOns list shows a consistent icon; bundle the 64x64 TGA in ZaeUI_Shared/Textures and keep the PNG/PSD source in assets/
• Update issue templates, PR template and the issue-labeler workflow to include ZaeUI_DungeonNotes
• luacheck: exclude ZaeUI_Shared/Libs from lint and register the new globals; project stays green on 25 files (0 warnings, 0 errors)
• Version bumps for every addon whose TOC was touched: ActionBars 1.2.3, Defensives 2.3.4, FriendlyPlates 1.2.9, Interrupts 2.3.3, Nameplates 2.2.3, Shared 1.3.0