v2.1.0-alpha.460

Changes

• feat: cross-fabric diagnostics with per-fabric metadata (b99869f)
• feat: add i18n foundation with react-i18next, EN+DE translations (573f11e)
• feat: add aria-label attributes to interactive UI elements (3a37f23)
• feat: populate per-entity cluster diagnostics in DiagnosticService (ba74108)
• feat: add unavailability indicator to endpoint tree view (e0ac880)
• feat: add Rain Sensor device type for binary_sensor entities (9ed657c)
• feat: broaden entity isolation to handle more error patterns (a29859a)

⚠️ This is an alpha release - use at your own risk!