fed-sx-types Phase 1: DefineType + SubtypeOf genesis verbs

Two new DefineActivity-form genesis activity-types for host-type
federation (plans/fed-sx-host-types.md step 1):

- next/genesis/activity-types/define_type.sx — DefineType verb; schema
  accepts an :object with a string :name and optional list :fields.
- next/genesis/activity-types/subtype_of.sx — SubtypeOf verb; schema
  accepts an :object carrying string :child-type-cid + :parent-type-cid.

Schema bodies use nested `get` (not keyword-threading) so they are
directly evaluatable — keywords are not callable getters in the kernel.
Both registered in manifest.sx (activity-types now 7); the four bootstrap
suites' bundle counts bumped (5->7, total 36->38).

Tests: next/tests/define_type.sh (7), subtype_of.sh (6) — parse shape,
schema accept/reject, term_codec envelope round-trip.

Also load follower_graph + delivery in bootstrap_start.sh: its check-26
publish path exercises outbox:compute_delivery_set/3 (follower_graph:new
+ delivery:delivery_set), which an m2 substrate change had left unloaded
in that suite — a pre-existing red unrelated to the count bump.

Conformance 771/771; all touched next/tests green.

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

next/tests/genesis_parse.sh

@@ -48,6 +48,14 @@ cat > "$TMPFILE" <<'EPOCHS'
 (eval "(first (parse (file-read \"next/genesis/activity-types/endorse.sx\")))")
 (epoch 200)
 (eval "(get (apply dict (rest (parse (file-read \"next/genesis/activity-types/endorse.sx\")))) :name)")
+(epoch 201)
+(eval "(first (parse (file-read \"next/genesis/activity-types/define_type.sx\")))")
+(epoch 202)
+(eval "(get (apply dict (rest (parse (file-read \"next/genesis/activity-types/define_type.sx\")))) :name)")
+(epoch 203)
+(eval "(first (parse (file-read \"next/genesis/activity-types/subtype_of.sx\")))")
+(epoch 204)
+(eval "(get (apply dict (rest (parse (file-read \"next/genesis/activity-types/subtype_of.sx\")))) :name)")
 (epoch 19)
 (eval "(len (get (apply dict (rest (parse (file-read \"next/genesis/manifest.sx\")))) :activity-types))")
 (epoch 30)
@@ -180,7 +188,11 @@ check 27 "announce.sx head form"        "DefineActivity"
 check 28 "announce.sx name is Announce" "Announce"
 check 29 "endorse.sx head form"         "DefineActivity"
 check 200 "endorse.sx name is Endorse"  "Endorse"
-check 19 "manifest has 5 activity-types" "5"
+check 201 "define_type.sx head form"    "DefineActivity"
+check 202 "define_type.sx name"         "DefineType"
+check 203 "subtype_of.sx head form"     "DefineActivity"
+check 204 "subtype_of.sx name"          "SubtypeOf"
+check 19 "manifest has 7 activity-types" "7"
 check 30 "sx-artifact.sx head form"     "DefineObject"
 check 31 "sx-artifact.sx name"          "SXArtifact"
 check 32 "note.sx name"                 "Note"