relations: Phase 1 schema + direct relations (rel facts, relate/unrelate, children/parents/related) + 22 tests

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

plans/relations-on-sx.md

@@ -18,7 +18,7 @@ links. Reuses `lib/datalog/` — does not reimplement the engine.
 
 ## Status (rolling)
 
-`bash lib/relations/conformance.sh` → **0/0** (not yet started)
+`bash lib/relations/conformance.sh` → **22/22** (Phase 1 complete)
 
 ## Ground rules
 
@@ -61,14 +61,14 @@ lib/relations/federation.sx
 
 ## Phase 1 — Schema + direct relations
 
-- [ ] `lib/relations/schema.sx` — `rel(Src, Dst, Kind)` fact projection; a small
+- [x] `lib/relations/schema.sx` — `rel(Src, Dst, Kind)` fact projection; a small
   kind vocabulary (`parent`, `member`, `reply`, `variant`, `origin`, …) kept open
-- [ ] `lib/relations/api.sx` — `(relations/relate src dst kind)` / `(unrelate …)`
+- [x] `lib/relations/api.sx` — `(relations/relate src dst kind)` / `(unrelate …)`
   over a live Datalog db (assert/retract); `(children-of db node kind)`,
   `(parents-of db node kind)`, `(related db node kind)`
-- [ ] `lib/relations/tests/direct.sx` — assert/retract, direct children/parents,
+- [x] `lib/relations/tests/direct.sx` — assert/retract, direct children/parents,
   kind filtering, unknown node → empty
-- [ ] `lib/relations/conformance.sh` + scoreboard
+- [x] `lib/relations/conformance.sh` + scoreboard
 
 ## Phase 2 — Reachability + cycles
 
@@ -100,7 +100,18 @@ lib/relations/federation.sx
 
 ## Progress log
 
-(loop fills this in)
+- **Phase 1 — schema + direct relations** (22/22). `schema.sx`: `rel(Src,Dst,Kind)`
+  fact constructor + accessors, open kind vocabulary (`parent member reply variant
+  origin link`), `relations-fact-valid?`/`relations-known-kind?`. `api.sx`: db built
+  via `dl-program-data facts relations-rules` (Phase 1 rules empty — direct queries
+  need none); `relations-children-of`/`-parents-of`/`-related` are plain `dl-query`
+  on the `rel` relation, plucking the bound column from substitution dicts;
+  current-db convenience layer (`relations/load!`, `relations/relate`,
+  `relations/unrelate`, `relations/children`/`parents`/`related`) over `dl-assert!`/
+  `dl-retract!`, mirroring lib/acl/api.sx. Tests cover direct children/parents, leaf/
+  root empties, kind isolation (parent query skips reply edge), retract, the api
+  layer, and schema/constructor shape. Note: query result order is nondeterministic
+  — tests use an order-insensitive `set=?`.
 
 ## Blockers