fix: Fixed SearchableSelect valid input behaviour and state handling

[abba-soptim]

Description

The SearchableSelect component, used in the ClassEditor for Package input among other places, had an internal state used to save the last valid input. This state was not updated by the InputWithControlButtons, resulting in mismatches in certain cases.
Now the state is synchronized across input field aswell as button actions.

Test Checklist

General Behavior

• Components reload automatically when data changes
• Editing features are disabled in readonly datasets
• Dialogs pre-select current dataset/graph
• Required fields are validated in dialogs
• Discarding unsaved changes opens a discard cancel confirm dialog

Global MenuBar

• Navigate to home page works
• File menu:
  • Import → Graph/SHACL works
  • Export → Graph/SHACL works
  • Share Snapshot works
  • Delete → Dataset/Graph works
• Edit menu:
  • New → Class works
  • New → Package works
  • Edit/View → Create/Edit/View Ontology works
  • Edit/View → Package works
  • Undo/Redo (Ctrl+Z / Ctrl+Y) works
  • Enable/Disable editing works
  • Manage/View namespaces works
  • Delete → Ontology/Package works
• View menu:
  • Changelog opens and shows current graph
  • Compare Graphs opens
  • Full SHACL works
• Help menu:
  • Help link works
  • Submit Feedback link works
  • About navigation works

Welcome Page

• Navigation to Editor works
• Tips are displayed
• Security and data information displayed
• Copyright and version information displayed

Editor - MenuBar

• Search function works with all filters (All Datasets, Current Dataset, Current Graph, Current Package)
• Search finds classes, attributes, associations, packages
• "Enable Editing" button appears for readonly datasets

Editor - Navigation

• Hierarchical display (Datasets → Graphs → Packages) works
• Selection is highlighted
• Selecting a class does not change dataset/graph/package selection
• Class selection stays open/highlighted when switching dataset/graph/package
• Datasets and graphs are collapsible
• Single click selects; double click or chevron toggles expand/collapse
• State persists on reload (non-browser)
• Context menus act on the dataset/graph/package they were opened on
• Hover labels show prefixes when configured
• Dataset context menu:
  • Import graph works (disabled in readonly datasets)
  • Share Snapshot works
  • Enable/Disable editing works
  • Manage/View namespaces works
  • Delete dataset works
• Graph context menu:
  • New package works (disabled in readonly datasets)
  • Undo/Redo works (only enabled when available)
  • Create Ontology
  • Edit Ontology (View Ontology in readonly)
  • Delete Ontology
  • Changelog navigation works
  • Compare dialog works
  • SHACL import/export/full view works (import disabled in readonly datasets)
  • Export graph works
  • Delete graph works (disabled in readonly datasets)
• Package context menu:
  • Create new class works (disabled in readonly datasets)
  • View/Edit package works
  • Copy URL works
  • Delete package works (disabled for external/default packages and readonly datasets)
• Class context menu:
  • Open class (editor) works
  • SHACL works
  • Delete class works (disabled in readonly datasets)

Editor - Package View

• Class diagram displays correctly
• Moving nodes works and layout changes persist after reload
• Loading animation shows while loading
• Info cards show when no package or no classes available
• Drag and zoom diagram works
• "Reset View" button works
• "Filter View" works
• "Reset Layout" button resets diagram to auto-generated layout
• Click on class opens class editor

Editor - Class Editor

• Display and edit class properties: Label, Namespace, Package, Derived from, Abstract, Stereotypes, Attributes, Associations, Comment
• Delete class works
• Save changes works
• Discard changes works
• Attribute Editor works
• Association Editor works
• attribute/association SHACL View works
• Class SHACL View works

Prefixes Page

• View, add, remove and edit namespaces works

Changelog Page

• Select graph and display write operations works
• Operations shown in reverse chronological order
• Detailed view of changed triples works
• Restoring graph to a version works

Compare Page

• Compare two graphs works