Adds generate/bridge_trace.py: a structured sink + serializer for
per-turn articulation-bridge trace records, following the exact
ADR-0040 telemetry sink pattern (JsonlBufferSink / JsonlFileSink /
FanOutSink, no wall-clock, redact-by-default).
Modifies generate/intent_bridge.py: articulate_with_intent() emits
one BridgeTraceRecord per call through a module-level opt-in sink
(attach_bridge_trace_sink / detach_bridge_trace_sink). When no
sink is attached the call is a pure no-op — zero behavior change on
all existing paths.
The record captures:
- intent_tag / intent_subject (classifier output)
- plan_subject / plan_predicate / plan_object (articulation slots)
- recalled_words_len / recalled_words_sample (grounding supply)
- pre_ground_obj (what the graph node held before ground_graph)
- post_ground_obj (what it held after, or same if no grounding ran)
- bridge_surface / bridge_useful (final output + usefulness gate)
- fallback_surface (the plan.surface the runtime falls back to)
This is the Phase 1 measurement instrumentation described in the
full-sentence output mastery plan. Phases 2-5 act on the data this
produces; Phase 1 itself is pure observation.
