[kreneskyp]

quire matrix silently discarded the engine's explanations of source-tag ranges and IDs outside the declared trace grammar. At quire-driver e7f6e89, ranges already produce range-in-trace-tag and IDs dropped after and already appear in unmatched_tags; selecting only coverage_matrix hid both.

Emit those existing engine facts as warnings on stderr in markdown, JSON and TSV. JSON diagnostics retain reason, path and line. Stdout matrix data, binding semantics and strict verdict stay unchanged. Source ranges remain forbidden by FR-050-AC-50/FR-051-AC-28; Trace lists continue to use the module-declared comma grammar. FR-026-AC-15 documents the behavior.

Validation: pre-fix regression fails; Rust/Python/TypeScript cases pass in every format, typed warning checks retain locations, and comma-list healthy controls restore strict success with no tag warnings. Full local workspace suite passes 279 tests (one deliberately ignored network test); lint and formatting pass. The real driver checkout's JSON matrix is byte-identical before/after, while stderr now names the six dropped quire-cache IDs and the forbidden ranges. Includes the one-line Linux-only unused-mut correction independently verified by PLAT-1149's green Linux CI.

Tracking: https://linear.app/agent-ix/issue/PLAT-1150. This PR changes no engine pin and is independent of PLAT-1149's fix stack.

[kreneskyp]

Lead review (diff only): PLAT-1150 quire matrix now sends engine diagnostics and unmatched trace tags to stderr (structured under JSON diagnostics) with stdout payload and strict verdict unchanged. After merging current main: FR-026-AC-15 collision resolved by renumbering this criterion to FR-026-AC-16; matrix.rs ported to the ix-cli-kit Record/DiagnosticFields stream types after #131. Gate: fmt-check and lint clean; tests green except it_144 (host lacks python jsonschema, not this change). No findings.