feat(editor): add WSTM (Stat Modifier Curve) open catalog format

Open replacement for the gtChanceTo*.dbc / gtRegen*.dbc /
gtCombatRatings.dbc family of "1D level-keyed curve" tables.
Each entry defines a single linear curve mapping character level
to a stat value: melee crit chance per level, mana regen per
spirit per level, base armor per level, etc.

Curves are linear: value(level) = baseValue + perLevelDelta *
(level - 1), with the result optionally scaled by a global
multiplier and clamped to a level range. Most stock WoW curves
fit this shape — the few that don't (cubic Combat Ratings) live
in the dedicated WCRR catalog with spline support.

Distinct from WCRR (Combat Rating conversion, integer ratings ->
percentages) and WSPC (Spell Power Cost buckets, per-spell
costs). WSTM is for the generic engine-side stat curves that
aren't per-spell or per-rating.

Seven curveKind values classify the major stat families (Crit /
Hit / Power / Regen / Resist / Mitigation / Misc), and each
curve carries its own [minLevel, maxLevel] applicability range
plus a multiplier for global scaling without retuning each
curve's slope.

Three preset emitters: --gen-stm (5 crit-related curves with
canonical 3.3.5a base+per-level scaling — MeleeCrit 5%+0.05/lvl
resolves to 8.95% at lvl 80), --gen-stm-regen (4 regen curves
including ManaPerSpirit and the Vanilla-era 3 rage/sec OOC
decay), --gen-stm-armor (3 armor/mitigation/resistance curves).

The info renderer demos resolveAtLevel(curveId, 80) inline as
the @lvl80 column — server admins can sanity-check what each
curve resolves to at character cap without writing test code.

Validation enforces id+name presence, curveKind 0..6,
minLevel<=maxLevel, no duplicate ids; warns on:
  - maxLevel > 80 (unreachable at WotLK cap)
  - multiplier=0 (curve always evaluates to 0)
  - multiplier<0 (inverts the curve — possibly intentional)
  - perLevelDelta<0 (curve shrinks with level — unusual)

Wired through the cross-format table; WSTM appears in all 18
cross-format utilities. Format count 93 -> 94; CLI flag count
1076 -> 1081.

tools/editor/cli_dispatch.cpp

@@ -138,6 +138,7 @@
 #include "cli_boss_encounters_catalog.hpp"
 #include "cli_instance_lockouts_catalog.hpp"
 #include "cli_stable_slots_catalog.hpp"
+#include "cli_stat_curves_catalog.hpp"
 #include "cli_quest_objective.hpp"
 #include "cli_quest_reward.hpp"
 #include "cli_clone.hpp"
@@ -317,6 +318,7 @@ constexpr DispatchFn kDispatchTable[] = {
     handleBossEncountersCatalog,
     handleInstanceLockoutsCatalog,
     handleStableSlotsCatalog,
+    handleStatCurvesCatalog,
     handleQuestObjective,
     handleQuestReward,
     handleClone,