feat(services): volume mounts + admin volume inventory (C1)

services.volumes JSONB [{type: volume|bind, source, target, read_only}]
mapped into every replica's container config at deploy and reconcile
time, hashed into the runtime spec so mount changes trigger
reconciliation. Mounted via existing docker.HostConfig.Mounts.

- RuntimeSpec.Volumes + specHash + mount.Mount mapping in createReplica
- Create/update service accepts volumes; PUT replaces the whole list
- Replica-count reconcile now goes through the deploy queue — the last
  raw `go` reconcile left that could race a build
- GET /admin/volumes inventories node volumes with in_use flags;
  DELETE /admin/volumes/:name removes unused ones (409 on in-use)
- CLI: services update --volume/--bind/--clear-volumes, volumes
  list|delete; MCP: services_update + volumes_list/delete
- Settings UI: Volumes section with mount editor
- Migration normalizes the nullable baseline column to NOT NULL [].

Verified live: deploy applies mounts to the container, docker
auto-creates named volumes, in-use deletion is refused.

Generated with [Devin](https://devin.ai)

Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

app/backend/internal/api/volumes.go

@@ -0,0 +1,105 @@
+package api
+
+import (
+	"net/http"
+	"time"
+
+	"containr/internal/docker"
+
+	"github.com/gin-gonic/gin"
+)
+
+// VolumeInfo is one docker volume plus whether any container mounts it.
+type VolumeInfo struct {
+	Name       string            `json:"name"`
+	Driver     string            `json:"driver"`
+	Mountpoint string            `json:"mountpoint"`
+	Scope      string            `json:"scope"`
+	InUse      bool              `json:"in_use"`
+	UsedBy     []string          `json:"used_by,omitempty"`
+	Labels     map[string]string `json:"labels,omitempty"`
+	CreatedAt  time.Time         `json:"created_at,omitempty"`
+}
+
+func dockerClientOr500(c *gin.Context) (*docker.Client, bool) {
+	v, exists := c.Get("docker_client")
+	if !exists || v == nil {
+		respondError(c, http.StatusInternalServerError, "INTERNAL", "Docker client not available")
+		return nil, false
+	}
+	return v.(*docker.Client), true
+}
+
+// handleAdminListVolumes returns the node's docker volume inventory with
+// in-use flags. Admin-only: mountpoints reveal host filesystem layout.
+func handleAdminListVolumes(c *gin.Context) {
+	client, ok := dockerClientOr500(c)
+	if !ok {
+		return
+	}
+	ctx := c.Request.Context()
+
+	vols, err := client.ListVolumes(ctx)
+	if err != nil {
+		respondError(c, http.StatusBadGateway, "DEPENDENCY_UNAVAILABLE", "Failed to list volumes: "+err.Error())
+		return
+	}
+
+	containers, err := client.ListContainers(ctx, true)
+	if err != nil {
+		respondError(c, http.StatusBadGateway, "DEPENDENCY_UNAVAILABLE", "Failed to list containers: "+err.Error())
+		return
+	}
+	inUse := map[string][]string{}
+	for _, cont := range containers {
+		for _, m := range cont.Mounts {
+			if m.Type == "volume" {
+				name := cont.ID[:12]
+				if len(cont.Names) > 0 {
+					name = cont.Names[0]
+				}
+				inUse[m.Name] = append(inUse[m.Name], name)
+			}
+		}
+	}
+
+	out := make([]VolumeInfo, 0, len(vols.Volumes))
+	for _, v := range vols.Volumes {
+		if v == nil {
+			continue
+		}
+		info := VolumeInfo{
+			Name:       v.Name,
+			Driver:     v.Driver,
+			Mountpoint: v.Mountpoint,
+			Scope:      v.Scope,
+			Labels:     v.Labels,
+			UsedBy:     inUse[v.Name],
+		}
+		info.InUse = len(info.UsedBy) > 0
+		if t, err := time.Parse(time.RFC3339Nano, v.CreatedAt); err == nil {
+			info.CreatedAt = t
+		}
+		out = append(out, info)
+	}
+	c.JSON(http.StatusOK, gin.H{"volumes": out})
+}
+
+// handleAdminDeleteVolume removes a docker volume. Docker refuses removal
+// of in-use volumes — that error is surfaced as a conflict.
+func handleAdminDeleteVolume(c *gin.Context) {
+	client, ok := dockerClientOr500(c)
+	if !ok {
+		return
+	}
+	name := c.Param("name")
+	if name == "" {
+		respondError(c, http.StatusBadRequest, "VALIDATION", "Volume name is required")
+		return
+	}
+	if err := client.RemoveVolume(c.Request.Context(), name, false); err != nil {
+		respondError(c, http.StatusConflict, "CONFLICT", "Failed to remove volume: "+err.Error())
+		return
+	}
+	c.JSON(http.StatusOK, gin.H{"deleted": name})
+}