fed-sx-m1: Step 1a — next/ skeleton + README + gitignore

next/.gitignore

@@ -0,0 +1 @@
+data/

next/README.md

@@ -0,0 +1,34 @@
+# next — fed-sx Milestone 1 kernel
+
+Single-instance, single-actor fed-sx server built as Erlang-on-SX modules.
+See `plans/fed-sx-design.md` for the architecture and
+`plans/fed-sx-milestone-1.md` for the build plan.
+
+## Layout
+
+```
+next/
+├── kernel/      Erlang-on-SX kernel modules (.erl, hot-loaded via code:load_binary/3)
+├── genesis/     SX source files for the genesis bootstrap bundle (DefineActivity, ...)
+├── tests/       Bash test scripts driving sx_server.exe via the epoch protocol
+└── data/        Runtime state — gitignored
+    ├── log/         per-actor JSONL outboxes
+    ├── objects/     CID-addressed artifacts on disk
+    ├── snapshots/   projection snapshots
+    ├── indexes/     derived projection index files
+    └── keys/        actor signing keys + bearer tokens
+```
+
+## Substrate
+
+The kernel is Erlang-on-SX. Each `.erl` source file is hot-loaded at boot via
+`code:load_binary(Mod, Filename, SourceString)` (Erlang Phase 7 BIF). The
+underlying SX runtime provides the host primitives the kernel calls into:
+`crypto:*`, `cid:*`, `file:*`, `code:*`, and (Step 8) `http:listen/2`.
+
+Tests drive the kernel via the epoch protocol:
+
+```bash
+printf '(epoch 1)\n(load "lib/erlang/runtime.sx")\n(epoch 2)\n<test-expr>\n' \
+  | hosts/ocaml/_build/default/bin/sx_server.exe
+```