feat(runners): Add suggested labels and label management

- Add DistroInfo struct to parse Linux distribution from capabilities
- Add runner label management endpoints (add/remove/use-suggested)
- Update runner edit UI with:
  - Clickable labels with X to remove
  - Suggested labels with + to add individually
  - Use All Suggested Labels button
  - Buttons moved to full-width row below columns
- Suggested labels derived from OS and distro (linux, linux-latest, debian, debian-latest, etc)

🤖 Generated with Claude Code

modules/structs/actions_capabilities.go

@@ -21,10 +21,18 @@ type DiskInfo struct {
 	UsedPercent float64 `json:"used_percent"`
 }
 
+// DistroInfo holds Linux distribution information
+type DistroInfo struct {
+	ID         string `json:"id,omitempty"`          // e.g., "ubuntu", "debian", "fedora"
+	VersionID  string `json:"version_id,omitempty"`  // e.g., "24.04", "12"
+	PrettyName string `json:"pretty_name,omitempty"` // e.g., "Ubuntu 24.04 LTS"
+}
+
 // RunnerCapability represents the detailed capabilities of a runner
 type RunnerCapability struct {
 	OS               string              `json:"os"`
 	Arch             string              `json:"arch"`
+	Distro           *DistroInfo         `json:"distro,omitempty"`
 	Docker           bool                `json:"docker"`
 	DockerCompose    bool                `json:"docker_compose"`
 	ContainerRuntime string              `json:"container_runtime,omitempty"`
@@ -34,6 +42,7 @@ type RunnerCapability struct {
 	Limitations      []string            `json:"limitations,omitempty"`
 	Disk             *DiskInfo           `json:"disk,omitempty"`
 	Bandwidth        *BandwidthInfo      `json:"bandwidth,omitempty"`
+	SuggestedLabels  []string            `json:"suggested_labels,omitempty"`
 }
 
 // CapabilityFeatures represents feature support flags