UX S3: SRD copy-edit pass — sanitize jargon + curated overrides

Plumbed through the open5e importer so regen stays safe:

- New cmd/open5e-import/desc_overrides.go holds two per-ID override
  maps (spellDescOverride, magicItemDescOverride) and a regex-driven
  cleanDesc sanitizer. Override wins outright; otherwise the SRD
  first-sentence runs through cleanDesc, which strips the phrases
  the S3 acceptance criteria forbid (saving throw[s], spell slot,
  within range, 5-foot, DC <n>, "(save DC X)" parentheticals,
  "constitution score is N", "out to a range of N feet"). A small
  post-pass repairs the orphan stubs the strippers leave behind
  (" and." trailers, "must make." after the saving-throw object
  is gone).

- gen.go (spells) + magicitems.go now call spellDescription /
  magicItemDescription instead of raw firstSentence; same hand-
  authored override pattern, same cleanDesc fallthrough.

- Override coverage: the 19 SRD-only spells that show up in
  defaultKnownSpells (call_lightning, charm_person, vicious_mockery,
  …) plus ~35 high-visibility magic items (Amulet of Health, every
  Belt of Giant Strength variant, Cloak of Displacement, etc.).
  Tone is outcome-first second-person with bite — these surface
  in the spellbook and the curio shop, so they get to be funny.

- tuned.go (R21) + magicitems.go strip "(...)" from emitted Names
  via stripNameParenthetical. Slug keeps the variant; only the
  display text loses the qualifier. Two bestiary entries
  (giant_rat_diseased, deep_gnome_svirfneblin) and stone_of_good_luck
  affected.

- Regenerated all three data files. Acceptance grep is clean:
  zero hits for any banned phrase in Description/Desc fields.

- New cmd/open5e-import/desc_overrides_test.go covers the
  sanitizer regressions, orphan-repair, name-strip, and the
  override-wins-but-fallthrough-still-sanitizes path.

Conflicts: none. S4 (magic-item UX) wanted this in first so the
new curio renderer consumes clean text — ready for it now.

cmd/open5e-import/magicitems.go

@@ -171,9 +171,9 @@ func genMagicItems() error {
 func classifyMagicItem(m open5eMagicItem) genMagicItem {
 	g := genMagicItem{
 		ID:         strings.ReplaceAll(m.Slug, "-", "_"),
-		Name:       m.Name,
+		Name:       stripNameParenthetical(m.Name),
 		Attunement: strings.TrimSpace(m.RequiresAttunement) != "",
-		Desc:       firstSentence(strings.TrimSpace(m.Desc), 200),
+		Desc:       magicItemDescription(strings.ReplaceAll(m.Slug, "-", "_"), strings.TrimSpace(m.Desc)),
 	}
 
 	rarity := strings.ToLower(strings.TrimSpace(m.Rarity))
@@ -250,6 +250,15 @@ func inferSlot(kind, name string) string {
 	return ""
 }
 
+// magicItemDescription returns the Desc text emitted for an item. Override
+// wins; otherwise the SRD first-sentence runs through cleanDesc.
+func magicItemDescription(id, raw string) string {
+	if s, ok := magicItemDescOverride[id]; ok {
+		return s
+	}
+	return firstSentence(cleanDesc(raw), 200)
+}
+
 // ── Code emission ────────────────────────────────────────────────────────────
 
 func emitMagicItems(items []genMagicItem) []byte {