merge: integrate upstream RPG attributes customization system

Merged commits from upstream/main (d870731):
- Add customizable RPG attributes (STR/DEX/etc) with add/remove/rename
- Fix character stats editing (0% display bug, missing Stats line creation)
- Add mobile font-size overrides for better readability
- Fix together mode rendering order (render panels before cleaning DOM)
- Fix temperature unit toggle (C/F) and thermometer thresholds
- Add buildAttributesString() for custom attribute names in AI prompts

Upstream Features:
- trackerConfig.rpgAttributes array replaces showRPGAttributes boolean
- Per-attribute enable/disable, custom names, reordering
- Tracker editor UI for managing attributes
- Custom attribute names appear in AI prompts and dice rolls
- Backward compatible migration from old boolean toggle

Merge Conflict Resolution:
- src/systems/integration/sillytavern.js:
  * Kept both: upstream's "render before DOM cleaning" + our refreshDashboard()
  * Result: render panels → refresh dashboard → update DOM
- style.css:
  * Kept both: our Widget Integration CSS + upstream's Mobile Font Overrides
  * Our Recent Events width fix (width: 100%) preserved

Related upstream commits:
- d870731: Add customizable RPG attributes and fix character stats editing
- f20710f: Make RPG attributes customizable and editable
- 883212b: Add comprehensive mobile font-size overrides
- 718696e: Fix multiple UI and functionality issues

No functional changes to v2 dashboard yet - integration in next commit.

style.css

@@ -7981,3 +7981,67 @@ body:has(.rpg-panel.rpg-position-left) #sheld {
 .rpg-widget-empty-state a:hover {
     opacity: 0.8;
 }
+
+/* ========================================
+   MOBILE FONT SIZE OVERRIDES (ALL SCREENS)
+   Apply to screens up to 1000px
+   ======================================== */
+@media (max-width: 1000px) {
+    /* Collapse toggle button */
+    .rpg-collapse-toggle {
+        font-size: clamp(16px, 3vw, 20px) !important;
+    }
+
+    /* Top position panel titles */
+    .rpg-panel.rpg-position-top .rpg-stats-title {
+        font-size: clamp(12px, 2.6vw, 16px) !important;
+    }
+
+    .rpg-panel.rpg-position-top .rpg-mood {
+        font-size: clamp(10px, 2vw, 13px) !important;
+    }
+
+    .rpg-panel.rpg-position-top .rpg-classic-stats-title {
+        font-size: clamp(10px, 2vw, 13px) !important;
+    }
+
+    .rpg-panel.rpg-position-top .rpg-classic-stat-label {
+        font-size: clamp(8px, 1.7vw, 11px) !important;
+    }
+
+    .rpg-panel.rpg-position-top .rpg-classic-stat-value {
+        font-size: clamp(12px, 2.6vw, 16px) !important;
+    }
+
+    .rpg-panel.rpg-position-top .rpg-classic-stat-btn {
+        font-size: clamp(10px, 2.2vw, 14px) !important;
+    }
+
+    .rpg-panel.rpg-position-top .rpg-info-content,
+    .rpg-panel.rpg-position-top .rpg-thoughts-content {
+        font-size: clamp(10px, 2.2vw, 14px) !important;
+    }
+
+    /* Panel header */
+    .rpg-panel-header h3 {
+        font-size: clamp(14px, 3.4vw, 18px) !important;
+    }
+
+    /* Loading indicator */
+    .rpg-loading {
+        font-size: clamp(12px, 2.6vw, 16px) !important;
+    }
+
+    /* Dice display */
+    .rpg-dice-display {
+        font-size: clamp(10px, 2vw, 13px) !important;
+    }
+
+    .rpg-dice-display i {
+        font-size: clamp(12px, 2.6vw, 16px) !important;
+    }
+
+    .rpg-clear-dice-btn {
+        font-size: clamp(14px, 3vw, 18px) !important;
+    }
+}