M6.18: Skill expansion to 5 per ability — 12 new Theriapolis-flavored skills

Skill list grows from 18 → 30 so every ability has 5 skills tied to it.
New skills appended at SkillId byte indices 18–29 to preserve
save-game compat with pre-M6.18 characters.

  STR (+4): Brawl, Build-Read, Force, Haulage
  DEX (+2): Driving, Marksmanship
  CON (+5): Endurance, Fortitude, Hardiness, Lung-Craft, Pain Tolerance
  CHA (+1): Scent-Speak

Endurance covers applied effort over time; Hardiness covers external
condition tolerance (temperature, smoke, altitude); Fortitude is
ingestion-only (poison, spoiled food, ritual draughts). Pain Tolerance
is function-while-wounded. Lung-Craft is breath/voice discipline.

Class skill_options updated across all 8 callings so every new skill
has 3+ class homes (Muzzle-Speaker remains the universal pick of
all 30). Backgrounds left untouched — their skill grants are
doc-canon and would benefit from a separate balancing pass.

CharacterBuilder.SkillToJsonName extended with explicit cases for the
new skills so compound enum names like BuildRead serialize as
"build_read" rather than the fallback "buildread" — caught by
CharacterBuilderTests.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

Theriapolis.Core/Rules/Character/CharacterBuilder.cs

@@ -401,6 +401,19 @@ public sealed class CharacterBuilder
         SkillId.SleightOfHand   => "sleight_of_hand",
         SkillId.Stealth         => "stealth",
         SkillId.Survival        => "survival",
+
+        SkillId.Brawl           => "brawl",
+        SkillId.BuildRead       => "build_read",
+        SkillId.Driving         => "driving",
+        SkillId.Endurance       => "endurance",
+        SkillId.Force           => "force",
+        SkillId.Fortitude       => "fortitude",
+        SkillId.Hardiness       => "hardiness",
+        SkillId.Haulage         => "haulage",
+        SkillId.LungCraft       => "lung_craft",
+        SkillId.Marksmanship    => "marksmanship",
+        SkillId.PainTolerance   => "pain_tolerance",
+        SkillId.ScentSpeak      => "scent_speak",
         _ => s.ToString().ToLowerInvariant(),
     };
 

Theriapolis.Core/Rules/Stats/SkillId.cs

@@ -1,8 +1,11 @@
 namespace Theriapolis.Core.Rules.Stats;
 
 /// <summary>
-/// Standard d20-adjacent skill list. Each skill is backed by a single
-/// ability — see <see cref="SkillAbility"/>.
+/// Skill list used by Theriapolis — extends the d20 baseline with 12
+/// additional skills (M6.18) so each ability has 5 skills tied to it.
+/// New skills appended at the end of the byte enum to preserve save-game
+/// compatibility with characters created before M6.18. Each skill is
+/// backed by a single ability — see <see cref="SkillIdExtensions.Ability"/>.
 /// </summary>
 public enum SkillId : byte
 {
@@ -24,6 +27,20 @@ public enum SkillId : byte
     SleightOfHand   = 15,
     Stealth         = 16,
     Survival        = 17,
+
+    // M6.18 — Theriapolis-flavored expansions, 5 per ability.
+    Brawl           = 18,   // STR
+    BuildRead       = 19,   // STR
+    Driving         = 20,   // DEX
+    Endurance       = 21,   // CON
+    Force           = 22,   // STR
+    Fortitude       = 23,   // CON
+    Hardiness       = 24,   // CON
+    Haulage         = 25,   // STR
+    LungCraft       = 26,   // CON
+    Marksmanship    = 27,   // DEX
+    PainTolerance   = 28,   // CON
+    ScentSpeak      = 29,   // CHA
 }
 
 public static class SkillIdExtensions
@@ -48,6 +65,19 @@ public static class SkillIdExtensions
         SkillId.SleightOfHand   => AbilityId.DEX,
         SkillId.Stealth         => AbilityId.DEX,
         SkillId.Survival        => AbilityId.WIS,
+
+        SkillId.Brawl           => AbilityId.STR,
+        SkillId.BuildRead       => AbilityId.STR,
+        SkillId.Driving         => AbilityId.DEX,
+        SkillId.Endurance       => AbilityId.CON,
+        SkillId.Force           => AbilityId.STR,
+        SkillId.Fortitude       => AbilityId.CON,
+        SkillId.Hardiness       => AbilityId.CON,
+        SkillId.Haulage         => AbilityId.STR,
+        SkillId.LungCraft       => AbilityId.CON,
+        SkillId.Marksmanship    => AbilityId.DEX,
+        SkillId.PainTolerance   => AbilityId.CON,
+        SkillId.ScentSpeak      => AbilityId.CHA,
         _ => throw new ArgumentOutOfRangeException(nameof(s)),
     };
 
@@ -72,6 +102,19 @@ public static class SkillIdExtensions
         "sleight_of_hand"   => SkillId.SleightOfHand,
         "stealth"           => SkillId.Stealth,
         "survival"          => SkillId.Survival,
+
+        "brawl"             => SkillId.Brawl,
+        "build_read"        => SkillId.BuildRead,
+        "driving"           => SkillId.Driving,
+        "endurance"         => SkillId.Endurance,
+        "force"             => SkillId.Force,
+        "fortitude"         => SkillId.Fortitude,
+        "hardiness"         => SkillId.Hardiness,
+        "haulage"           => SkillId.Haulage,
+        "lung_craft"        => SkillId.LungCraft,
+        "marksmanship"      => SkillId.Marksmanship,
+        "pain_tolerance"    => SkillId.PainTolerance,
+        "scent_speak"       => SkillId.ScentSpeak,
         _ => throw new ArgumentException($"Unknown skill: '{raw}'"),
     };
 }