build: consume the shared traceability tooling via submodule

jray-project is added at scripts/vendor/jray-project and the extractor is used
from there. Only two files are repo-local: traceability.toml, which carries
everything repo-specific, and the CI workflow that invokes the vendored gate.

The extractor is deliberately NOT copied in. One implementation, parameterised
by config — a second copy would drift from the first, and the tool already
proves it works unchanged against all three registers.

Enables system_spec so PR/SR orphan checking runs: previously uncheckable,
because the system spec lived outside every component's checkout.

Gate is green at 0.0% of 63 requirements, which is correct — nothing is tagged
yet. Eleven are flagged unverifiable on this CI host and excluded from the
numerator rather than counted.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

traceability.toml

@@ -0,0 +1,34 @@
+# Traceability configuration for scene-actor-extraction.
+#
+# Read by the shared extractor (scripts/traceability/extract_traces.py), which
+# is the same implementation every JRay component uses. Everything repo-specific
+# lives here rather than in the tool; run `extract_traces.py
+# --print-example-config` for the annotated schema.
+#
+# This file's directory is taken as the repo root, so the gate works from any
+# subdirectory.
+
+# The prefixes this repo's register defines. Nothing else enters the fraction:
+# UT/IT are evidence for requirements, PR/SR belong to the system spec.
+requirement_types = ["AR", "DP", "IR", "GR", "VR"]
+
+# C++ pipeline plus the Python tooling, optimizer and validation scripts.
+languages = ["cpp", "python"]
+
+source_roots = ["src", "tests", "scripts", "experiments", "eval"]
+
+# CI is an Intel N100 with no discrete GPU. T4 is deliberately absent: a
+# requirement verifiable only on GPU hardware is reported as tagged but
+# unexecuted and never counted as covered, because counting a test that cannot
+# run is the same failure mode as JellyTau's 158% coverage bug.
+ci_executable_tiers = ["T1", "T2", "T3", "static"]
+
+# Threshold policy. 0 today because almost nothing is tagged yet - tags land as
+# the pipeline is built. This is not a gate that cannot fail: orphan tags, a
+# >100% ratio, a register that parses to nothing and an empty source scan are
+# all hard failures already. Ratchet this up as tags land; never reset it down.
+min_coverage = 0.0
+
+# The system spec owning PR/SR is vendored per-component as a submodule. Point
+# at it once that lands to turn on PR/SR orphan checking:
+system_spec = "scripts/vendor/jray-project/SPEC.md"