docs: unify documentation and streamline code comments

- Translated project documentation (LEARNING-JOURNEY, CONTRIBUTORS, AI_DISCLOSURE) to English for better accessibility.
- Standardized internal code documentation by converting XML-doc blocks to standard comment format.
- Cleaned up inline comments and removed redundant versioning metadata across the codebase.
- Refactored non-functional text elements to improve readability and maintain a consistent style.

HellionChat/Themes/Builtin/HellionSpectrum.cs

@@ -2,12 +2,7 @@ using HellionChat.Util;
 
 namespace HellionChat.Themes.Builtin;
 
-// Hellion Spectrum: Deuteran/Protan-safe channel colours.
-// Palette derived from Bang Wong, "Points of view: Color blindness",
-// Nature Methods 8, 441 (2011). Channel identity (Tell pink, Yell yellow,
-// Shout orange, Party blue, FC green) is preserved per Channel-Identity-
-// Rule in docs/THEME-AUTHORING.md; tones are chosen so every channel
-// stays distinguishable under red-green colour-vision deficiency.
+// Deuteran/Protan-safe palette with preserved channel identity.
 internal static class HellionSpectrum
 {
     public const string Slug = "hellion-spectrum";
@@ -57,9 +52,6 @@ internal static class HellionSpectrum
             ChatColors: new ThemeChatColors(
                 new Dictionary<HellionChat.Code.ChatType, uint>
                 {
-                    // Hellion Spectrum — Wong/Okabe-Ito tones within FFXIV channel
-                    // identity. FC pulled slightly greener than vanilla cyan-teal so
-                    // Party-blue and FC-green stay separable under deuteran sim.
                     [HellionChat.Code.ChatType.Say] = ColourUtil.HexToRgba("#FFFFFF"),
                     [HellionChat.Code.ChatType.Yell] = ColourUtil.HexToRgba("#F0E442"),
                     [HellionChat.Code.ChatType.Shout] = ColourUtil.HexToRgba("#D55E00"),