sx delivered most of the foundation since the plan was written: alias
re-exports instead of pub, the modules/std.sx facade barrel, and native
std fs/process/json/cli/hash/log/test/socket/mem. Replace the 'sx
Foundation Work' section with as-built status + remaining gaps, mark
Phase 0 done / Phase 1 partial, note the superseded subplan-01 slices,
and drop the retired flow-harness execution contract (subplan 08, roles,
checkpoint files).
Document the already-decided decomposition of subplan-02 Slice 1 so the
P2.1 boundary is verifiable from the repo:
- P2.1 = Core Structs + boundary validation (validation portion of Slice 1)
- P2.3 = in-memory repository + db.json (rest of Slice 1)
- Token = Slice 5 (Token Security), out of both
Planning-doc record only; no domain or test code changed.
