Add shared core attribute allocation

docs/DESIGN_SYSTEM.md

@@ -757,6 +757,51 @@ each keystroke does not create a navigation entry. Retain an explicit Search
 button for immediate submission and keyboard/accessibility fallback. During
 navigation, expose a textual pending state and suppress duplicate submissions.
 
+Builder option grids support an icon-only square mode for small, icon-led
+catalogs such as a gear item's two-to-four compatible Brand Sets. In this mode,
+the compact 58-pixel cells reset the ordinary text-and-icon grid to a single
+centered track, and the transparent icon fills that square. Align the fieldset
+with adjacent compact controls rather than inheriting the standard radio-grid
+top margin. Visible truncated names are omitted. Preserve the complete name as
+the radio control's accessible label and
+as hover text. Selection, hover, pressed, and keyboard-focus states remain on
+the square perimeter; missing icons fall back to the entity initials.
+
+Builder level controls enforce item availability without changing the scaling
+curve's origin. T0 and T1 gear and weapons allow levels 1–50; T2 gear and
+weapons allow levels 40–50 because lower-level T2 items are not found in game.
+Their base-value progression still follows the same level-1-based curve.
+Selecting T2 on a weapon below level 40 raises the configured level to 40 and
+calculates the ordinary level-40 curve value; never rebase level 40 as T2 level
+1. Slider bounds, direct-input validation, displayed bounds, and clamping must
+all enforce the same availability minimum.
+
+ISAC weapon-tier damage and core ranges are observations recorded at their
+explicit reference level. The progression curve still has a level-1 origin,
+but builder scaling must calculate the ratio between the target level and the
+stored observation's `reference_level`. Do not treat every stored endpoint as a
+level-1 value merely because the curve begins there.
+
+### Shared core allocation
+
+Firepower, Toughness, and Engineering use one system-wide tier profile shared
+by gear and weapons. Maintain the T0/T1/T2 nominal ranges in ISAC Global
+Configuration rather than repeating them on every item editor. The initial
+level-50 profiles are T0 `30–78`, T1 `36–94`, and T2 `44–112`. Global
+configuration mutations follow ordinary contributor moderation and append-only
+ISAC audit rules.
+
+The three nominal ranges define a combined allocation pool, not three hard
+per-stat clamps. At a given level, the valid total lies between three times the
+scaled nominal minimum and three times the scaled nominal maximum. An
+individual core may be zero or exceed the nominal maximum when points are
+redistributed, up to the entire pool maximum. Builder gear and weapon editors
+show three sliders/direct inputs plus an explicit current-total versus
+valid-pool readout; out-of-pool totals use textual red/restricted feedback.
+Both equipment families contribute their configured cores to the build summary.
+Treat this redistribution model as empirical and keep it configurable as more
+in-game edge cases are observed.
+
 Pending records may be used as dependencies in later proposals by any
 contributor. Render these choices in the ordinary assignment control with a
 restrained orange border/background and the explicit text `PENDING` plus the

docs/STAT_LEVEL_SCALING.md

@@ -150,6 +150,19 @@ targetRaw =
   / weaponMultiplier(referenceLevel)
 ```
 
+SHD.build stores the reference level associated with each weapon-tier range.
+Builder calculations use that recorded observation level in the ratio above.
+The curve's level-1 origin does not imply that every stored range was observed
+at level 1. T2 availability limits likewise do not change a range's recorded
+reference level.
+
+Firepower, Toughness, and Engineering nominal tier ranges are stored once in
+the shared core-allocation configuration at reference level 50. Scale those
+nominal endpoints to the target level using the appropriate equipment-family
+multiplier, then derive the combined pool bounds by multiplying each endpoint
+by three. Redistribution changes the split between the three cores without
+changing the selected item's total allocation.
+
 The `1.14` offset is provisional and is currently validated only for the
 level-40-to-level-50 interval. Preserve enough decimal precision to revise it
 without migrating rounded data.
@@ -217,4 +230,3 @@ Useful known outputs include:
   `2187 DMG`, `139 FP`, `142 TGH`, `36 ENG`.
 - Weapon sample: level 40 `753 DMG`, `44 FP`, `15 TGH`, `45 ENG`; level 50
   `873 DMG`, `51 FP`, `18 TGH`, `52 ENG`.
-