feat: record bounded stock queue traces and latch sink failures

[EHotwagner]

Summary

Add a bounded same-read stock queue trace and permanent sink-failure latch. Preserve dispatch, stock supported-fields scheme2, finite float32 values and held-writer custody.

Source/interface review is READY for the exact HighBar/FSBar/private-supervisor join. Native BAR journeys remain 0/6; optional custom FR remains inactive. No engine executable rebuild, installation, publication or gameplay acceptance is claimed.

Evidence and verification

• Candidate 233b11f541986ee65e17062e2eed8548e795fd94, tree 8f287693d61ff7fcbdbd1e21482c70a09133e2fc, from owning master 03de478075a588bcc93b8a9ca25cb05006a7355a.
• Exact tree equals reviewed native candidate 9e04f4b68863436bcc0ab4cc70c82dfe9d0a7167.
• Native source tests and stock-header plugin build passed at that tree; independent failure-latch and descriptor regressions passed. Hosted CI remains required before source delivery; optional self-hosted native checks do not imply a live engine run.
• Independent final join report SHA256 8af519af1d014663538752dc913663d5eb787f431fec9f8944d9c1b10e54ab25: actual O_APPEND host descriptor, 17 helper tests, 28 codec/normalizer tests, healthy authenticated append during actual normalization; R1/R2/R3 resolved and prior B4/B5 preserved.