feat(rules): magic subsystem — spells, spell strength, LLW spell selection

[StreamDemon]

Adds the magic layer — the defining Ley Line Walker capability, and the last major LLW-specific subsystem.

What's included

• schema/spells.ts + content/spells/spells.json — 29 spells across levels 1–4, transcribed from RUE Magic Spells (Range / Duration / Saving Throw / P.P.E. / effect), each page-stamped. Covers the iconic ones: Armor of Ithan (10 M.D.C./level), Energy Bolt (4D6, dodge 18+), Globe of Daylight, See the Invisible, Charismatic Aura, …
• engine/spells.ts:
  • validated spell book with id + name indexes (collision-checked, same fail-fast pattern as skills)
  • spellsByLevel, canCast (P.P.E. affordability), getSpell/getSpellByName
  • Spell Strength (RUE p.187) — base 12, +1 at each O.C.C. increment level; the d20 a victim must beat to save vs the caster's magic
  • occSpellStrength() derives it from the LLW's own spellStrength bonus: 12 at L1 → 13/14/15/16 at L3/7/10/13
  • initialSpellChoices() realizes the LLW's "3 spells from each of levels 1–4" against the real spell list

Verification

• vp run rules#test → 59 tests pass (8 new spell tests)
• vp run rules#check → format + lint + typecheck clean

With this, the Ley Line Walker vertical slice is essentially complete end-to-end (attributes → O.C.C. → P.P.E. → combat/HP → skills → spells). Next up: the Convex backend to seed + serve the validated content and persist built characters.

---

Summary by cubic

Adds the magic subsystem for Ley Line Walkers: a validated spell book (29 spells, levels 1–4), Spell Strength, and initial spell selection (3 per level). Also fixes how flat O.C.C. Spell Strength bonuses are applied.

• New Features

  • Content: 29 spells (levels 1–4) with Range/Duration/Saving Throw/P.P.E./page in content/spells/spells.json.
  • Schema: schema/spells.ts Zod types for spells/book, plus spellStrengthBase (12) and ritualSaveTarget (16).
  • Engine: engine/spells.ts with id/name indexes, getSpell/getSpellByName, spellsByLevel, canCast, Spell Strength via occSpellStrength (+1 at LLW 3/7/10/13), saveTargetVsSpell, and initialSpellChoices for "3 from each level 1–4".
  • Exports: index.ts exposes the schema and engine.
  • Tests: coverage for lookups, grouping, P.P.E. checks, Spell Strength, and LLW selection.

• Bug Fixes

  • Correctly apply flat (non-level-gated) spellStrength bonuses using spellStrengthFromBonus; level-gated bonuses still increment per listed levels.

^{Written for commit cceeefc. Summary will update on new commits.}

[cubic-dev-ai]

1 issue found across 5 files

<sub>Reply with feedback, questions, or to request a fix.

Re-trigger cubic</sub>

[cubic-dev-ai]

0 issues found across 2 files (changes from recent commits).

<sub>Auto-approved: Adds new magic subsystem: spells schema/content (29 spells), spell strength calculus, and Ley Line Walker initial selection. Low-risk additive change with tests.

Re-trigger cubic</sub>