Changelog for Story Modeller 26.15.0

Changes

• Bump phoenix, plug, hpax, mint for security advisories (PR, #7977)
• Edit incident template colors, auto-assigned from a palette (PR, #7978)
• Upgrade Elixir to 1.20.2 and Erlang to 29.0.3 (PR, #7797)
• Add “Run with Casting” modal for stories (PR, #7936)
• Handle asset types with large numbers of assets (PR, #7935)
• Upgrade Node to 24.18.0 (PR, #7800)
• Upgrade Tailwind to 4.3.3 and altworx_ui_components to v6.7.0 (PR, #7802)
• Merge event template notifications into one switch with routing tag (PR, #7961)
• Upgrade Phoenix to 1.8.9 and LiveView to 1.2.7 (PR, #7798)