feat(plugins): ADR-098 Part 1 (slice 3/4) — cost-tracker federation pairing

Adds ADR-097 federation budget circuit breaker references to
ruflo-cost-tracker. The federation_send max_hops / max_tokens /
max_usd surface is exactly the boundary this plugin should track —
flagging it now even though the bus integration (Phase 3) is
deferred.

ruflo-cost-tracker/README.md:
  New "Federation budget circuit breaker pairing (ruflo 3.6.25+)"
  section with:
  - Field table: maxHops (default 8), maxTokens, maxUsd, hopCount,
    spent.{tokens,usd}
  - Phase 1 (shipped): enforce at send side
  - Phase 2 (deferred): peer state machine ACTIVE/SUSPENDED/EVICTED
    with $5/24h cost threshold + 50%/1h failure ratio triggers
  - Phase 3 (deferred): federation_spend event bus → per-peer
    rolling windows aggregated by this plugin → breaker queries
    aggregate
  - Honest caveat: until Phase 3, federated spend is NOT counted
    in cost-report — treat as lower bound when federation is in use

Related Plugins gains a ruflo-federation entry calling out the
ADR-097 dependency.

Plugin version: 0.1.0 → 0.2.0 (minor — capability sync).

ADR-098 Part 1 progress: 3/4 slices done. Last slice covers
ruflo-agentdb + ruflo-knowledge-graph (G7 controllers — gnnService,
rvfOptimizer, mutationGuard, attestationLog, GuardedVectorBackend).

plugins/ruflo-cost-tracker/.claude-plugin/plugin.json

@@ -1,7 +1,7 @@
 {
   "name": "ruflo-cost-tracker",
   "description": "Token usage tracking, model cost attribution per agent, budget alerts, and optimization recommendations",
-  "version": "0.1.0",
+  "version": "0.2.0",
   "author": {
     "name": "ruvnet",
     "url": "https://github.com/ruvnet"

plugins/ruflo-cost-tracker/README.md

@@ -62,10 +62,30 @@ cost history                             # Show cost tracking over time
 | Use Agent Booster (Tier 1) | 100% | Only for simple transforms |
 | Shorten system prompts | 10-20% | Requires careful pruning |
 
+## Federation budget circuit breaker pairing (ruflo 3.6.25+)
+
+This plugin pairs naturally with the federation budget envelope shipped in [ADR-097](../../v3/docs/adr/ADR-097-federation-budget-circuit-breaker.md). The `federation_send` MCP tool now accepts caller-supplied caps that this plugin's tracking should respect:
+
+| Field | Default | Effect |
+|---|---|---|
+| `maxHops` | `8` | Hard ceiling on recursive delegation across federated peers — defangs cost cascades from runaway sub-swarms. |
+| `maxTokens` | unbounded | Σ tokens across the whole hop chain. Returns `BUDGET_EXCEEDED` (constant string, no oracle leak) on overshoot. |
+| `maxUsd` | unbounded | Σ USD across hops. Same enforcement. |
+| `hopCount` | `0` | Pass-through for re-forwarded messages. |
+| `spent.{tokens,usd}` | `0` | Caller-reported usage from previous legs. Negatives clamped to 0. |
+
+Phase 1 of ADR-097 enforces at the **send** side. Two follow-up phases will tighten the integration:
+
+- **Phase 2 (deferred)** — peer state machine `ACTIVE` / `SUSPENDED` / `EVICTED` driven by trailing 24h cost (default suspension threshold $5) + 1h failure ratio (>50% over ≥10 sends). Auto-recovery after 30 min cooldown.
+- **Phase 3 (deferred)** — `federation_spend` event bus. Each `federation_send` completion publishes `{peerId, taskId, tokensUsed, usdSpent, ts}`. This plugin's cost-tracker should aggregate per-peer rolling windows (1h / 24h / 7d) and expose them via the existing `cost-report` skill. Breaker queries the aggregate to evaluate suspension thresholds.
+
+Until Phase 3 ships, federated spend is **not** counted in the host's cost-tracker — only local agent spend. Treat `cost-report` numbers as a lower bound when federation is in use.
+
 ## Related Plugins
 
 - `ruflo-observability` -- Token usage metrics collected via observability instrumentation
 - `ruflo-neural-trader` -- PnL tracking and cost-adjusted return calculation
+- `ruflo-federation` -- Budget circuit breaker on outbound federation_send (ADR-097)
 
 ## License