feat(plugin): add Survival Stats admin Studio plugin (deltas-only, locked tuning)

A Studio dock widget that lets the experience owner tune the survival stats
through a validated form instead of hand-editing Attributes on the
SurvivalStatsConfig instance — the first slice of the Builder/Admin plugin (#11).

The point is compatibility: edits are LOCKED against engine updates. StatAdmin
(the pure, headlessly-testable logic layer) writes deltas only — it sets an
attribute solely when the owner changes a field from the live engine default,
and removes it on reset / edit-back-to-default. So unset fields keep following
the (improvable) engine defaults across a SurvivorCore release, while explicit
overrides live on the owner's instance, which the engine only ever seeds and
never overwrites. Nothing tuned is lost; nothing left alone is frozen.

Hard guardrail: the plugin can read/write only the seven owner-tunable fields
(STUDIO_ATTR_MAP). A write() assert makes it impossible to ever set the
engine-owned semantics Invert / DangerHigh — re-freezing the affliction
fill-direction bug is structurally unreachable. Runtime-verified in Studio:
every write path exercised (including rejected Invert/DangerHigh attempts) left
zero banned attributes on the instance.

- plugin/StatAdmin.luau     — logic: roster, effective values, deltas-only writes
- plugin/StatAdminUi.luau   — the dock-widget form (per-field reset, override dots)
- plugin/init.server.luau   — toolbar/widget wiring + ChangeHistory undo steps
- plugin.project.json       — separate Rojo tree; build with --plugin to install
- CI: stylua + a plugin-sourcemap luau-lsp pass + a plugin build
- docs/admin-plugin.md + cross-links; fix stale Invert row in the no-code table

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

.github/workflows/ci.yml

@@ -26,7 +26,7 @@ jobs:
         uses: CompeyDev/setup-rokit@v0.1.2
 
       - name: StyLua (format check)
-        run: stylua --check src demo assets
+        run: stylua --check src demo assets plugin
 
       - name: Selene (lint)
         run: selene .
@@ -51,9 +51,20 @@ jobs:
             --ignore "ServerPackages/**" \
             src demo assets/client
 
-      # Prove both Rojo targets build: the drop-in engine model and the runnable demo place.
+      # The Studio admin plugin is a separate Rojo tree (its requires resolve against its own
+      # sourcemap, not the demo's), so analyze it with the plugin sourcemap.
+      - name: Generate plugin sourcemap
+        run: rojo sourcemap plugin.project.json --output plugin-sourcemap.json
+
+      - name: luau-lsp (plugin)
+        run: luau-lsp analyze --sourcemap plugin-sourcemap.json --defs globalTypes.d.luau --no-strict-dm-types plugin
+
+      # Prove every Rojo target builds: the drop-in engine model, the demo place, the plugin.
       - name: Build engine model (default.project.json)
         run: rojo build default.project.json --output SurvivorCore.rbxm
 
       - name: Build demo place (demo.project.json)
         run: rojo build demo.project.json --output demo.rbxl
+
+      - name: Build admin plugin (plugin.project.json)
+        run: rojo build plugin.project.json --output SurvivorCoreStatAdmin.rbxm