[Stephen Belanger (Qard)]

Adds the concrete SQLite SpanOp channel before production activation. Translation output is published atomically with its input position, including empty and chunked output. Each routing subscription has its own durable head and completion capability; explicit storage codecs preserve fields skipped by public SpanOp serialization.

Storage is compiled and tested without activating a parallel production path. Three focused tests cover incomplete writes/restart, independent heads and cancellation, and injected head-write failure followed by confirmed recovery. Journal path validation and empty reads use explicit handling rather than panic assumptions. Retains the Windows console probe compilation timeout fix.

Based on main at ece990c, including merged #176. Preserves the checked-delivery SDK pin and main's Rustls security updates alongside the SQLite dependencies.

Pipeline layer 4; base: main (includes #176).

Validation at c18fe22: all 519 tests pass in the locked all-feature Rust suite without exclusions or environment overrides; five live-agent tests remain normally ignored. Strict all-target/all-feature Clippy, formatting, and diff checks pass.

Rebased at a8f34a9: all three commits retain identical patches (git range-diff); diff checks pass. Tests are left to fresh CI as requested.