audit fixes, repo restructure, and documentation

Soundness and performance audit (17 fixes):
- See AUDIT.md for full details and @claude comments in code

Repo restructure:
- Inline json-ptr and json-patch submodules as regular directories
- Remove cbor submodule, replace serde_cbor with ciborium
- Rename patch-db/ -> core/, patch-db-macro/ -> macro/,
  patch-db-macro-internals/ -> macro-internals/, patch-db-util/ -> util/
- Purge upstream CI/CD, bench, and release cruft from json-patch
- Remove .gitmodules

Test fixes:
- Fix proptest doesnt_crash (unique file paths, proper close/cleanup)
- Add PatchDb::close() for clean teardown

Documentation:
- Add README.md, ARCHITECTURE.md, CONTRIBUTING.md, CLAUDE.md, AUDIT.md
- Add TSDocs to TypeScript client exports

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

core/src/test.rs

@@ -0,0 +1,105 @@
+use std::future::Future;
+use std::sync::atomic::{AtomicUsize, Ordering};
+use std::sync::Arc;
+
+use imbl_value::{json, Value};
+use json_ptr::JsonPointer;
+use patch_db::{HasModel, PatchDb, Revision};
+use proptest::prelude::*;
+use tokio::fs;
+use tokio::runtime::Builder;
+
+use crate::{self as patch_db};
+
+/// Atomic counter to generate unique file paths across concurrent tests.
+static TEST_COUNTER: AtomicUsize = AtomicUsize::new(0);
+
+fn unique_db_path(prefix: &str) -> String {
+    let id = TEST_COUNTER.fetch_add(1, Ordering::Relaxed);
+    format!("test-{}-{}.db", prefix, id)
+}
+
+async fn init_db(db_name: String) -> PatchDb {
+    cleanup_db(&db_name).await;
+    let db = PatchDb::open(db_name).await.unwrap();
+    db.put(
+        &JsonPointer::<&'static str>::default(),
+        &json!({
+            "a": "test1",
+            "b": {
+                "a": "test2",
+                "b": 1,
+                "c": null,
+            },
+        }),
+    )
+    .await
+    .unwrap();
+    db
+}
+
+async fn cleanup_db(db_name: &str) {
+    fs::remove_file(db_name).await.ok();
+    fs::remove_file(format!("{}.bak", db_name)).await.ok();
+    fs::remove_file(format!("{}.bak.tmp", db_name)).await.ok();
+    fs::remove_file(format!("{}.failed", db_name)).await.ok();
+}
+
+async fn put_string_into_root(db: &PatchDb, s: String) -> Arc<Revision> {
+    db.put(&JsonPointer::<&'static str>::default(), &s)
+        .await
+        .unwrap()
+        .unwrap()
+}
+
+#[tokio::test]
+async fn basic() {
+    let path = unique_db_path("basic");
+    let db = init_db(path.clone()).await;
+    let ptr: JsonPointer = "/b/b".parse().unwrap();
+    let mut get_res: Value = db.get(&ptr).await.unwrap();
+    assert_eq!(get_res.as_u64(), Some(1));
+    db.put(&ptr, "hello").await.unwrap();
+    get_res = db.get(&ptr).await.unwrap();
+    assert_eq!(get_res.as_str(), Some("hello"));
+    db.close().await.unwrap();
+    cleanup_db(&path).await;
+}
+
+fn run_future<S: Into<String>, Fut: Future<Output = ()>>(name: S, fut: Fut) {
+    Builder::new_multi_thread()
+        .thread_name(name)
+        .build()
+        .unwrap()
+        .block_on(fut)
+}
+
+proptest! {
+    #[test]
+    fn doesnt_crash(s in "\\PC*") {
+        run_future("test-doesnt-crash", async {
+            let path = unique_db_path("proptest");
+            let db = init_db(path.clone()).await;
+            put_string_into_root(&db, s).await;
+            db.close().await.unwrap();
+            cleanup_db(&path).await;
+        });
+    }
+}
+
+// #[derive(Debug, serde::Deserialize, serde::Serialize, HasModel)]
+// pub struct Sample {
+//     a: String,
+//     #[model]
+//     b: Child,
+// }
+
+// #[derive(Debug, serde::Deserialize, serde::Serialize, HasModel)]
+// pub struct Child {
+//     a: String,
+//     b: usize,
+//     c: NewType,
+// }
+
+// #[derive(Debug, serde::Deserialize, serde::Serialize, HasModel)]
+// pub struct NewType(Option<Box<Sample>>);