feat(dashboard): PropertyEditorShared extraction + UX quality overhaul

Extract shared components (PropertyRow, PropertyCard, AddPropertyDialog,
FollowerSelector, EmptyFollowerState) into PropertyEditorShared.js,
eliminating ~300 lines of duplication between SafetyLimitsEditor and
FollowerConfigEditor.

- SafetyLimitsEditor: 991 → 296 lines via shared components
- FollowerConfigEditor: 1352 → 634 lines, fully schema-driven
- NESTED_SUBSECTIONS registry in followerConfigSchemaUtils — adding
  new nested sub-sections requires zero editor code changes
- Override UX: left border indicator, badge chips, hover-reveal delete
- Bug fixes: slider defaults, sparse write-back, enum display,
  add-override button, reference hints in AddPropertyDialog

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: alireza787b

configs/config_schema.yaml

@@ -2965,6 +2965,16 @@ sections:
         reboot_required: true
         min: 0
         max: 10000
+      General:
+        type: object
+        description: Shared follower operational defaults (v6.1.0+)
+        reload_tier: follower_restart
+        reboot_required: false
+      FollowerOverrides:
+        type: object
+        description: Per-follower operational config overrides (sparse)
+        reload_tier: follower_restart
+        reboot_required: false
   FOLLOWER_CIRCUIT_BREAKER:
     type: boolean
     default: true