feat(fp.job.step): wrap button_finish with gate + advance (Task 4)

Pre-super: when finishing the last open step on an in_progress job,
run the bake/qty/QC gates from button_mark_done so failures surface
as UserError on the click (per spec D12). Without this the
auto-advance would silently fail with no error path.

Post-super: trigger _fp_check_advance_post_shop so the state
auto-advances cleanly (in_progress → awaiting_cert / awaiting_ship).

Added _fp_check_finish_gates helper on fp.job and a
fp_check_gates_only context flag honored by button_mark_done so the
gate logic is single-sourced (DRY).

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

fusion_plating/fusion_plating_jobs/models/fp_job.py

@@ -1984,6 +1984,11 @@ class FpJob(models.Model):
                         "Job %s requires QC. A new check has been created — "
                         "complete it before marking the job Done."
                     ) % job.name)
+            # When called as a gate-check from fp.job.step.button_finish
+            # (per spec 2026-05-25 D12), exit BEFORE flipping state —
+            # the post-shop advance helper handles the actual transition.
+            if self.env.context.get('fp_check_gates_only'):
+                continue
             job.state = 'done'
             job.date_finished = fields.Datetime.now()
             if not skip_side_effects:
@@ -2153,6 +2158,30 @@ class FpJob(models.Model):
     # regresses awaiting_ship → awaiting_cert. All helpers are
     # idempotent — safe to call from any hook.
     # ==================================================================
+    def _fp_check_finish_gates(self):
+        """Run the bake-window / qty-reconciliation / QC gates that used
+        to live in button_mark_done. Called from
+        fp.job.step.button_finish when the operator is finishing the
+        LAST open step on the job (spec D12).
+
+        Raises UserError on failure — operator stays on the step, fixes
+        the issue, retries the click. Manager bypass via the same
+        context flags as button_mark_done (fp_skip_bake_gate,
+        fp_skip_qty_reconcile, fp_skip_qc_gate).
+
+        The trick: re-uses button_mark_done's gate logic but short-
+        circuits BEFORE the state flip via the fp_check_gates_only
+        context flag (honoured in button_mark_done below).
+        """
+        self.ensure_one()
+        # Pass through with context flag; button_mark_done will run all
+        # its gates and then exit before flipping state. The actual
+        # state transition (in_progress → awaiting_cert/ship) is owned
+        # by _fp_check_advance_post_shop running AFTER super().button_finish.
+        self.with_context(
+            fp_check_gates_only=True,
+        ).button_mark_done()
+
     def _fp_check_advance_post_shop(self):
         """Auto-advance in_progress jobs whose recipe steps are all
         terminal. Called from fp.job.step.button_finish post-super().

fusion_plating/fusion_plating_jobs/models/fp_job_step.py

@@ -1311,8 +1311,36 @@ class FpJobStep(models.Model):
         self._fp_check_contract_review_complete()
         self._fp_check_receiving_gate()
 
+        # ----- Post-shop gate (spec 2026-05-25 D12) ---------------------
+        # When finishing the LAST open step on an in_progress job, run
+        # the bake/qty/QC gates that used to live in button_mark_done.
+        # Failure raises UserError on THIS click — operator fixes
+        # (qty, bake, QC) and retries the finish. Without this the
+        # auto-advance helper would silently fail with no error path.
+        for step in self:
+            if step.state not in ('in_progress', 'paused', 'ready'):
+                continue
+            job = step.job_id
+            if not job or job.state != 'in_progress':
+                continue
+            # Would this finish leave every step terminal?
+            siblings_open = job.step_ids.filtered(
+                lambda s: s.id != step.id
+                and s.state not in ('done', 'skipped', 'cancelled')
+            )
+            if siblings_open:
+                continue  # not the last open step — skip the gates
+            job._fp_check_finish_gates()
+
         result = super().button_finish()
 
+        # ----- Post-shop auto-advance (spec 2026-05-25) -----------------
+        # After super().button_finish flips step state to done, ask the
+        # job to check whether ALL steps are now terminal. If so the
+        # helper auto-advances state to awaiting_cert / awaiting_ship.
+        for job in self.mapped('job_id'):
+            job._fp_check_advance_post_shop()
+
         # ----- Post-finish side effects --------------------------------
         BW = self.env['fusion.plating.bake.window']
         Bath = self.env['fusion.plating.bath']