Make the repo usable by external users: license, submodule docs, honest platform errors

LICENSE

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2026 Taylor Gagne
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

README.md

@@ -70,16 +70,24 @@ vendor/           Vendored tree-sitter core and grammars
 - Git
 - vcpkg (a local copy is fine — see step 2). Dependencies `curl`, `igraph`,
   `nlohmann-json`, and `utf8proc` are declared in `vcpkg.json` and built
-  automatically on first configure. `tree-sitter` is vendored under
-  `vendor/tree-sitter`.
+  automatically on first configure. `tree-sitter` is vendored as git
+  submodules under `vendor/tree-sitter` (see step 1).
 
 ### 1. Clone
 
 ```sh
-git clone https://github.com/taylor009/CGraph.git
+git clone --recurse-submodules https://github.com/taylor009/CGraph.git
 cd CGraph
 ```
 
+The tree-sitter core and grammars under `vendor/tree-sitter` are git
+submodules — the build fails without them. If you already cloned without
+`--recurse-submodules`, fetch them with:
+
+```sh
+git submodule update --init --recursive
+```
+
 ### 2. Point CMake at vcpkg
 
 The presets read the toolchain from `$VCPKG_ROOT/scripts/buildsystems/vcpkg.cmake`,

src/cli/main.cpp

@@ -525,6 +525,14 @@ std::filesystem::path supervisor_config_path() {
 
 // cgraph daemon <install|sync|status|uninstall> [flags]
 int run_daemon_command(int argc, char** argv) {
+#if !defined(__APPLE__)
+  (void)argc;
+  (void)argv;
+  std::cerr << "cgraph daemon: launchd-based supervision is only supported on macOS. "
+               "On this platform run `graphd --root PATH` directly (or supervise it "
+               "with your init system, e.g. a systemd user unit).\n";
+  return 1;
+#endif
   const std::string sub = argc >= 3 ? argv[2] : "";
   if (sub != "install" && sub != "sync" && sub != "status" && sub != "uninstall") {
     std::cerr << "usage: cgraph daemon <install|sync|status|uninstall> "
@@ -683,6 +691,14 @@ int run_skills_command(int argc, char** argv) {
 // cgraph drain <install|status|uninstall> [--interval SECONDS] [--chunk-cap N]
 //              [--script PATH] [--launch-agents-dir DIR] [--client PATH]
 int run_drain_command(int argc, char** argv) {
+#if !defined(__APPLE__)
+  (void)argc;
+  (void)argv;
+  std::cerr << "cgraph drain: the launchd-based enrichment drainer is only supported on "
+               "macOS. On this platform run integrations/always-on/cgraph-enrich-drain.sh "
+               "on a schedule (e.g. cron or a systemd timer).\n";
+  return 1;
+#endif
   const std::string sub = argc >= 3 ? argv[2] : "";
   if (sub != "install" && sub != "status" && sub != "uninstall") {
     std::cerr << "usage: cgraph drain <install|status|uninstall> [--interval SECONDS] "