feat: Build Manager, Crucible ops deck, branding, and portable Cloudflare tunnel

Add Build Manager with pin-to-dropper, Crucible multi-node terminal with SSH probe/wake, Command Deck chart balance and pretty stats, AetherForge logo and sacred geometry UI, Field Guide refresh, and LAUNCH.bat Cloudflare MSI + token service install flow.

server/internal/models/agent.go

@@ -33,6 +33,9 @@ type Agent struct {
 	OSVersion string `json:"os_version,omitempty"`
 
 	Capabilities *AgentCapabilities `json:"capabilities,omitempty"`
+
+	// Crucible — SSH status probed by the agent every ~60s
+	SSHAvailable *bool `json:"ssh_available,omitempty"`
 }
 
 // AgentCapabilities reports forge-time features available for remote command.
@@ -87,6 +90,7 @@ type BuildRecord struct {
 	DownloadURL string    `json:"download_url"` // relative URL; client prepends server origin
 	Platform    string    `json:"platform"`     // "windows", "linux", "darwin", "universal"
 	CreatedAt   time.Time `json:"created_at"`
+	Pinned      bool      `json:"pinned"` // true = this build is served by /get and /install.*
 	// Pool settings
 	PoolHost string `json:"pool_host"`
 	PoolPort int    `json:"pool_port"`