Summary

Today the Property Inspector requires you to type the Workspace, Client, Project and
Task names by hand and match them exactly to what exists in Clockify. A single typo
silently results in no timer being found.

This PR turns those four fields into live dropdowns populated directly from your
Clockify account, with a per-field freetext fallback so nothing is lost when manual
entry is needed.

What's new

• Cascading dropdowns in the Property Inspector:
  • Workspace → loads its Clients and Projects
  • Client → filters the Project list
  • Project → loads its Tasks
• Freetext toggle (✎) per field — switch any field back to manual entry (useful when
  the API is unreachable, a list is very long, or you want to create a brand-new task
  that does not exist yet).
• Auto-load on open plus a "Refresh lists from Clockify" button.
• Existing settings are pre-selected on open (full backward compatibility — the stored
  values remain the human-readable names, not IDs).

How it works

• A new read-only ClockifyLookupService performs the lookups (workspaces / clients /
  projects / tasks → name lists). It is stateless and shares no state with the existing
  ClockifyService.
• The Property Inspector talks to the plugin over the standard
  sendToPlugin / sendToPropertyInspector channel; ToggleAction handles the requests
  in OnSendToPlugin and replies via SendToPropertyInspectorAsync. The way settings are
  persisted is unchanged.
• A small clockify-pi.js drives the cascading UI; the vendored EasyPI library is left
  untouched.

Backward compatibility

• PluginSettings only gains four optional *Manual boolean flags (default false).
  Existing buttons keep working unchanged; stored values remain human-readable names.

Testing

• Unit tests for the name-normalization logic (LookupMapping) pass.
• Builds clean for win-x64.
• Manually verified in the Stream Deck app: dropdowns populate after entering the API key,
  the cascade filters correctly, existing selections are restored, the freetext toggle
  round-trips across reopen, refresh works, and starting/stopping a timer still works.