Generate browser-safe workbench operation inventory

[mkilijanek]

Problem
Workbench uses a hand-maintained browser-safe whitelist in packages/workbench/src/plugins/builtins.ts. The UI shows only a small subset of shipped operations and drifts from the real plugin inventory.

Outcome
Create a generated browser-safe operation inventory for workbench consumption.

Scope

• define browser-safe or runtime-target metadata for operations or generated inventory entries
• generate a workbench-consumable inventory from plugins-standard instead of a handwritten list
• remove catalog drift between shipped operations and UI-visible operations
• add regression tests for inventory generation and browser-safe filtering