feat(workspace): per-kind step action buttons in Job Workspace

Fix: in the Job Workspace tablet view, the Start button was buried
inside a parent t-if that required the step to already be in_progress
or blocked. So ready/paused steps showed no buttons at all -
operators couldn't advance the WO from this screen (the reason the
user couldn't complete anything on WO-30057).

Template restructure (job_workspace.xml):
- Always-visible line 1 (icon + step# + name + ACTIVE/PAUSED badge + meta)
- Non-terminal detail panel (chips + instructions + opt-out + GateViz)
  visible on every non-done step so operator reads ahead
- Action row dispatched per-kind via getStepActions() helper

Per-kind action dispatcher (job_workspace.js):
- in_progress -> Record Inputs, Pause, Finish (or Finish & Sign Off)
- paused      -> Resume, Record Inputs, Finish
- contract_review (ready) -> Open QA-005 Form
- gating (ready)          -> Mark Passed (1-click start+finish)
- requires_rack_assignment -> Start (Assign Rack) - opens FpRackPartsDialog
- else (ready)            -> Start

5 new handlers: onPauseStep / onResumeStep / onMarkPassed /
onOpenContractReview / onStartWithRack. Pause and Resume use ORM RPC
(button_pause/button_resume) since no HTTP endpoint exists.

New model method (fp.job.step.action_mark_gating_passed):
- 1-click pass for gating steps - does button_start + button_finish
  in one transaction, posts chatter "Gate X marked passed by Y"
- Raises UserError if called on a non-gating step (defensive)
- Bypasses S21 required-inputs gate (gating steps have no inputs)

Controller: workspace_controller.py adds requires_rack_assignment to
the step payload so the JS dispatcher can route correctly.

Spec: docs/superpowers/specs/2026-05-24-workspace-step-actions-design.md
Sub-B (Record Inputs tablet polish: inputmode/prefill/date pickers/
signature pad/camera) is brainstormed but deferred.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

fusion_plating/fusion_plating_shopfloor/controllers/workspace_controller.py

@@ -89,6 +89,9 @@ class FpWorkspaceController(http.Controller):
                 'dwell_time_minutes': step.dwell_time_minutes or 0,
                 'bake_setpoint_temp': step.bake_setpoint_temp or 0,
                 'requires_signoff': bool(getattr(step, 'requires_signoff', False)),
+                'requires_rack_assignment': bool(getattr(
+                    step, 'requires_rack_assignment', False,
+                )),
                 'can_start': bool(step.can_start) if 'can_start' in step._fields else (
                     step.state in ('ready', 'paused') and step.blocker_kind == 'none'
                 ),