refactor(plugins): dedup workflow engine handlers into shared helpers

[SamTolmay]

Extract the logic that was copy-pasted across the WorkflowAPI handlers
into shared, single-source helpers (no behavior change):

• shared/collectionNames.js — collection-name defaults, previously
  repeated in 8 files (schema-default drift risk).
• shared/findWorkflowConfig.js — workflowsConfig lookup by type,
  previously repeated in 6 files.
• shared/render/resolveActionAccess.js — add hasAnyVerb +
  selectVisibleActions (the access-filter + link-collapse + annotate
  loop repeated in the three card-rendering read handlers).
• shared/render/pruneFormData.js — the ~50-line form_data pruning block
  duplicated verbatim in GetWorkflowOverview and
  GetWorkflowActionGroupOverview.
• shared/render/buildEntityLink.js — the entity_link chrome built in
  four handlers.
• shared/render/collectActionGroups.js — the action_group grouping +
  declaration-order/unseen-group indexing duplicated in
  GetEntityWorkflows and GetWorkflowOverview.
• WorkflowAPI/shared/terminateWorkflow.js — the identical
  sweep → recompute → references-merge → event → change-log →
  tracker-fire → commit → cascade tail of CancelWorkflow and
  CloseWorkflow; the handlers now declare only their documented deltas
  (lifecycle stage, event/tracker signals, sweep exception).

Structural cleanup:

• Move GetEventsTimeline under connections/EventsTimeline/ — it is
  registered on the EventsTimeline connection, not WorkflowAPI.
• Move dispatchNotifications to shared/phases/ — its only caller is
  commitPlan, which previously imported it from inside WorkflowAPI
  (inverted dependency).
• Delete SubmitWorkflowAction/UserError.js — dead code, never imported.
• GetEventsTimeline: fold the two card branches (workflow / non-workflow)
  into one card shape with a conditional access gate.
• GetWorkflowAction: fix the out-of-order step comments; build
  entity_link from the guarded entityId (no TypeError when a doc lacks
  entity).
• WorkflowAPI schema: eventsCollection is read by GetWorkflowAction only
  (GetEventsTimeline belongs to the EventsTimeline connection).

Co-Authored-By: Claude Fable 5 noreply@anthropic.com
Claude-Session: https://claude.ai/code/session_01QqkWUK5HgZTsXck38Sm5bh