ottl(pattern-2): node_infiniband -> hw.network.ib.* recipe

[trilamsr]

Problem

The pattern-#2 (InfiniBand link flap) detector library + processor wiring shipped in earlier work and the operator-facing walkthrough lands in #391 (closes #300). But the metrics→logs OTTL recipe that projects node_infiniband_port_state_id (from node_exporter --collector.infiniband) onto the customer-stable hw.network.ib.* log-record namespace has not landed. Until it does, the detector is configured-but-quiet on a real deployment — no input ever arrives at the projector.

Sibling gap pattern to #284 / #285 (PCIe AER OTTL stanzas) and gated on the broader RFC-0014 PR-B metrics→logs bridge.

Customer-stable contract (already declared)

Wire shape the OTTL recipe must produce (verified against module/processor/patterndetectorprocessor/ib_link_flap.go projector + docs/ATTRIBUTES.md):

• hw.network.ib.port.state — int, IBA-spec phys_state ID (1=Down, 2=Initialize, 3=Armed, 4=Active).
• hw.network.ib.device — string, per-NIC device name (e.g. mlx5_0).
• hw.network.ib.port.num — int, IB port index (typically 1 or 2 on ConnectX boards).
• Resource: k8s.node.name (stamped by k8sattributes).

One log record per scrape per (device, port) tuple.

Proposed recipe shape

Extends docs/integrations/prometheus-scrape.md with an IB stanza. Source series: node_infiniband_port_state_id{device, port, instance}. OTTL projection:

• set(attributes["hw.network.ib.device"], attributes["device"])
• set(attributes["hw.network.ib.port.num"], Int(attributes["port"]))
• set(attributes["hw.network.ib.port.state"], Int(value))

(Approximate — final shape resolved during impl alongside the metrics-to-logs bridge in RFC-0014 PR-B.)

Acceptance

• docs/integrations/prometheus-scrape.md carries an IB stanza producing the wire shape above.
• An end-to-end test in module/processor/patterndetectorprocessor/ round-trips the recipe output through IBLinkFlapDetector and asserts a verdict fires.
• The "Integration gap" section in docs/patterns/pattern-2-ib-link-flap.md can be deleted (or flipped to "shipped").

References

• Walkthrough: docs/patterns/pattern-2-ib-link-flap.md (PR docs(pattern-2): author IB link flap operator walkthrough #391, closes docs(pattern-2): author InfiniBand link flap walkthrough (blocks detector PR) #300)
• Detector library: module/pkg/patterns/ib_link_flap.go
• Processor wiring: module/processor/patterndetectorprocessor/ib_link_flap.go
• ATTRIBUTES contract: docs/ATTRIBUTES.md §hw.network.*
• RFC-0014: docs/rfcs/0014-metrics-to-logs-pattern-input.md (gates this work)
• Sibling gaps: OTTL recipe: derive tracecore.alert.pcie_rate_collapse.* from hw.gpu.io counter (pattern #5 wiring) #284, Recipe extension: journald-kernel OTTL stanza for PCIe AER (kernelevents.pcie_aer.*) #285 (PCIe AER OTTL stanzas)