B2b: decommission orchestration + missing-storage indicator + re-enroll fix (v0.65.0)

agentapi.Decommission + handleStorageDecommission (migrate-all-or-none, Change 2):
migrate-then-decommission via the migration done-hook, or decommission-anyway (stop
apps, keep HDD_PATH). 'Hiányzó tárhely' badge on dashboard/stacks/app card when an
app's drive is decommissioned/disconnected/absent. Change 4: registerStoragePath
clears the decommissioned marker on re-enroll (ClearDecommissioned had no callers).
Non-hollow tests incl. mutation-proven Change-4 companion.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

controller/internal/stacks/migrate.go

@@ -115,6 +115,11 @@ type MigrationJob struct {
 	StartedAt  time.Time           `json:"started_at"`
 	UpdatedAt  time.Time           `json:"updated_at"`
 	FinishedAt time.Time           `json:"finished_at,omitempty"`
+
+	// DecommissionOnDone: when set, the migration was started by the decommission flow — on successful
+	// completion the done-hook soft-marks the source registry path + tells the agent to decommission it.
+	// The engine itself does NOT decommission; it only fires the hook (the policy lives in the caller).
+	DecommissionOnDone bool `json:"decommission_on_done,omitempty"`
 }
 
 func (j *MigrationJob) clone() *MigrationJob {
@@ -185,17 +190,27 @@ func (m *Manager) MigrationStatus() *MigrationJob {
 	return m.migJob.clone()
 }
 
+// SetMigrationDoneHook registers a callback fired (in the migration goroutine) when a migration
+// completes successfully. The decommission flow uses it to soft-mark + agent-decommission the source.
+func (m *Manager) SetMigrationDoneHook(fn func(*MigrationJob)) { m.migDoneHook = fn }
+
 // MigrateAll moves the whole namespace off sourcePath onto targetPath.
 func (m *Manager) MigrateAll(ctx context.Context, sourcePath, targetPath string) (string, error) {
-	return m.startMigration("all", sourcePath, "", targetPath)
+	return m.startMigration("all", sourcePath, "", targetPath, false)
+}
+
+// MigrateAllAndDecommission moves the whole namespace then (on success) fires the done-hook so the
+// caller decommissions the now-empty source drive.
+func (m *Manager) MigrateAllAndDecommission(ctx context.Context, sourcePath, targetPath string) (string, error) {
+	return m.startMigration("all", sourcePath, "", targetPath, true)
 }
 
 // MigrateApp moves a single app's data subtree onto targetPath.
 func (m *Manager) MigrateApp(ctx context.Context, appName, targetPath string) (string, error) {
-	return m.startMigration("app", "", appName, targetPath)
+	return m.startMigration("app", "", appName, targetPath, false)
 }
 
-func (m *Manager) startMigration(scope, sourcePath, appName, targetPath string) (string, error) {
+func (m *Manager) startMigration(scope, sourcePath, appName, targetPath string, decommission bool) (string, error) {
 	if err := m.acquireMigrating(); err != nil {
 		return "", err
 	}
@@ -207,10 +222,11 @@ func (m *Manager) startMigration(scope, sourcePath, appName, targetPath string)
 	}()
 
 	j := &MigrationJob{
-		Scope:     scope,
-		Target:    filepath.Clean(targetPath),
-		Units:     map[string]*MigUnit{},
-		StartedAt: time.Now().UTC(),
+		Scope:              scope,
+		Target:             filepath.Clean(targetPath),
+		Units:              map[string]*MigUnit{},
+		StartedAt:          time.Now().UTC(),
+		DecommissionOnDone: decommission,
 	}
 	j.ID = "mig-" + j.StartedAt.Format("20060102-150405")
 
@@ -389,6 +405,9 @@ func (m *Manager) runMigration(ctx context.Context, j *MigrationJob) {
 		}
 		if j.Phase == PhaseDone {
 			m.logger.Printf("[INFO] [migrate] %s complete: %s → %s (%d app(s))", j.ID, j.Source, j.Target, len(j.Apps))
+			if m.migDoneHook != nil {
+				m.migDoneHook(j.clone()) // decommission policy (soft-mark + agent) lives in the hook
+			}
 			return
 		}
 	}