feat: real user flow validation scripts + heartbeat timing fixes

[bussyjd]

Summary

Introduces pi-autoresearch integration for automated real user flow validation, plus Go bug fixes and doc corrections discovered during the overnight run.

Commit 1: Flow scripts + autoresearch harness

10 bash flow scripts that exercise every documented user journey from docs/getting-started.md and docs/guides/monetize-inference.md:

flows/
├── lib.sh                     # Shared harness (step/pass/fail/poll, Anvil credentials)
├── flow-01-prerequisites.sh   # Docker, Ollama, obol binary
├── flow-02-stack-init-up.sh   # getting-started §1-2
├── flow-03-inference.sh       # getting-started §3a-3d (LiteLLM, tool-calls)
├── flow-04-agent.sh           # getting-started §4-5 (agent init, inference)
├── flow-05-network.sh         # getting-started §6 (network add/remove)
├── flow-06-sell-setup.sh      # monetize §1.1-1.4 (pricing, ServiceOffer, heartbeat)
├── flow-07-sell-verify.sh     # monetize §1.5-1.7 (tunnel, routes, 402, metrics)
├── flow-08-buy.sh             # monetize §2 (discovery, EIP-712 payment, settlement)
├── flow-09-lifecycle.sh       # monetize §4 (stop, delete, cleanup)
└── flow-10-anvil-facilitator.sh  # monetize §3 (Anvil fork, x402-rs facilitator)

All commands use the real obol binary — no go run, no direct kubectl, no pod IP access.

Commit 2: Bug fixes found by the flow scripts

Timing (closes #280):

• ensureHeartbeatActive() — heartbeat was stuck at 30m default after obol agent init
• patchHeartbeatAfterSync() — SyncAgentBaseURL helmfile sync was resetting heartbeat config
• readCurrentAgentBaseURL() — skip sync when tunnel URL unchanged (idempotency)

CLI validation:

• validateRPCEndpoint() in obol network add — reject invalid URLs

Doc corrections:

• getting-started §3c-3d: add LiteLLM Bearer auth header (was returning 401)
• monetize §1.6: correct eRPC path to /rpc/evm/{chainId} (local-only, not via tunnel)
• monetize §2.1: clarify /skill.md (always available) vs /.well-known (requires --register)

Discovery method

Overnight pi-autoresearch session: 44 → 133 steps passing across 50+ experiments. The agent autonomously ran flow scripts, diagnosed failures, fixed Go code and flow scripts, and re-validated — all while go build/go test acted as backpressure.

Test plan

• go build ./... passes
• go test ./internal/{agent,tunnel,network,openclaw,model}/ passes
• pi-autoresearch: 133/133 steps, 50+ runs
• Manual: bash flows/flow-01-prerequisites.sh through flow-09-lifecycle.sh on fresh cluster