feat(ui): spellcasting cast-button + character-panel attribute/skill tooltips — gmSpellcastingUI::UpdateCastButtonTooltip @0x004C6A30, AttributeInfoRegion/Attribute2ndInfoRegion/SkillInfoRegion @0x004F1530/0x004F1680/0x004F2140

TS-85 remainder batch (hover/UI overnight round, batch B). Audit found
three of the four listed spellcasting SetTooltip sites (endowment icon,
favorite, submenu) were already correct via UiCatalogSlot's pre-existing
Label-driven GetTooltipText; only the cast button (UiButton, no tooltip
wiring at all) was a real gap. Ports the verified literal states
("Select a spell to cast" / "You have no spells ready to cast" / the
full endowment-item USE-the-%s branch) plus a documented, narrower
fallback (spell name only) for the one sub-branch whose exact wording
sits behind a genuine gmNoticeHandler vtable-slot collision in the
pseudo-C dump rather than the unlabeled-string-pool class the rest of
this batch recovered.

Character panel: new UiClickablePanel.TooltipText seam (same pattern as
UiButton.TooltipText) carries the six hardcoded attribute descriptions
and three pair-shared vitals descriptions (byte-decoded from the retail
string pool) plus skill tooltips composed from the already-DAT-parsed
SkillBase.Description/.Formula — no hand-transcription needed for the
~30+ skill strings. The formula-to-text algorithm itself
(SkillSystem::InqSkillFormula) was recovered by byte-decoding six short
fragments Binary Ninja left completely unlabeled between two
gmSpellcastingUI vtable declarations.

Live-verified against the local ACE server: 34 real skills' composed
tooltips and both reachable cast-button states captured via a temporary
probe (stripped before this commit). Full solution suite green
(14,647 tests, 0 failures) both before and after the probe strip.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

tests/AcDream.App.Tests/UI/Layout/SpellcastingUiControllerTests.cs

@@ -152,6 +152,13 @@ public sealed class SpellcastingUiControllerTests
             CurrentlyEquippedLocation = EquipMask.Held,
             SpellId = 2670u,
             IconId = 0x06001234u,
+            // TS-85: gmSpellcastingUI::UpdateCastButtonTooltip's endowment
+            // branch (0x004c6a30) gates immediate-use on
+            // ItemUses::IsUseable_SelfTarget (0x004fcd30) reading the ITEM's
+            // own Useability target mask -- a self-castable orb authors the
+            // Self target bit so clicking Cast fires without a target
+            // selection, matching this test's intent.
+            Useability = (ItemUseability.Self << 16) | ItemUseability.Wielded,
         });
         controller.Tick();