P3.4a: dist ci publish happy path + persistence (manifest->store->validate->publish->db.json->JSON)

Real local publish success pipeline replacing the ci-publish stub: validate manifest,
find/create app + draft release, per-artifact content-address store (P2.2) + common
validation (P3.3) with optional manifest-declared size/sha256 (PO ruling), publish via
the repo integrity transaction with channel promotion + audit events (P2.3), persist
db.json (P2.3), emit stable JSON (release id, artifact ids, sha256, file:// URLs) with
--json purity. make publish-example target + tests/publish_happy.sx (fail-before/pass-after).

Salvaged from a worker that completed the work (make test 10/10) but hit the 50-min wall
before committing; manager-verified at ground truth (make test green, make publish-example
exit 0, stored object re-hashes to its key via shasum, db.json records release/2 artifacts/
channel/4 audit events).

src/repo/db.sx

@@ -21,6 +21,10 @@
 
 #import "modules/std.sx";
 #import "modules/std/json.sx";
+// Also reached through an alias so the json reader is called as `jsonp.parse`
+// — a bare `parse` would bind to `std.cli`'s `parse` once both modules share
+// one program (the `dist` CLI), which returns a different type.
+jsonp :: #import "modules/std/json.sx";
 #import "modules/fs.sx";
 #import "../domain/platform.sx";
 #import "../domain/app.sx";
@@ -360,7 +364,7 @@ audit_from_json :: (o: Object, alloc: Allocator) -> (AuditEvent, !LoadErr) {
 load_into :: (repo: *Repo, bytes: string, scratch: Allocator) -> !LoadErr {
     oa := repo.own_allocator;
 
-    root_val, pe := parse(bytes, scratch);
+    root_val, pe := jsonp.parse(bytes, scratch);
     if pe { raise error.Parse; }
     ro := try req_obj(root_val);