Build a filterable plugin catalog and selection UI #4

Context

Users should be able to browse a controlled list and choose only the plugins relevant to their instruments and workflow.

Depends on the catalog/schema issue and the catalog-based installation service. Related strategy decision: #1.

Scope

Extend or replace the current desktop Plugin Manager screen with a catalog view supporting:

• text search
• category filters
• instrument filters
• source/maintainer filter
• stability filter
• installed / available / update-available filter
• compatibility and requirements indicators
• multi-select followed by one install action

Each card/row should show the plugin name, description, version, category, source, stability, download size, installed state, and relevant compatibility information.

Selection behavior

• Automatically select required dependencies and explain why they were added.
• Prevent deselecting a dependency while another selected plugin requires it.
• Report conflicts before downloading.
• Disable incompatible entries with an actionable explanation.
• Keep recommendations distinct from hard requirements.
• Never silently install optional recommendations.
• Show the final resolved installation set before confirmation.

Accessibility and resilience

• Keyboard-accessible filters and selection controls.
• Screen-reader labels and visible focus states.
• Useful empty, offline, loading, and error states.
• The bundled catalog remains browsable offline; installation clearly reports when a network connection is required.

Acceptance criteria

• Users can combine multiple filters and clear them.
• Dependency changes are visible before installation.
• Installed, bundled, and writable-override states are distinguishable.
• The UI invokes only the main-process installation API; the renderer does not write plugin files.
• Tests cover filtering, dependency selection, conflicts, and incompatible entries.