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/Cargo.toml

@@ -0,0 +1,48 @@
+[package]
+authors = ["Aiden McClelland <aiden@start9labs.com>"]
+categories = ["database-implementations"]
+description = "A database that tracks state updates as RFC 6902 JSON Patches"
+edition = "2018"
+keywords = ["json", "json-pointer", "json-patch"]
+license = "MIT"
+name = "patch-db"
+readme = "README.md"
+repository = "https://github.com/Start9Labs/patch-db"
+version = "0.1.0"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+[features]
+debug = ["tracing"]
+trace = ["debug", "tracing-error"]
+unstable = []
+
+[dependencies]
+async-trait = "0.1.42"
+fd-lock-rs = "0.1.3"
+futures = "0.3.8"
+imbl = "6"
+imbl-value = "0.4.1"
+json-patch = { path = "../json-patch" }
+json-ptr = { path = "../json-ptr" }
+lazy_static = "1.4.0"
+tracing = { version = "0.1.29", optional = true }
+tracing-error = { version = "0.2.0", optional = true }
+nix = "0.30.1"
+patch-db-macro = { path = "../macro" }
+serde = { version = "1", features = ["rc"] }
+ciborium = "0.2"
+thiserror = "2"
+tokio = { version = "1", features = ["sync", "fs", "rt", "io-util", "macros"] }
+
+[dev-dependencies]
+proptest = "1.0.0"
+serde = { version = "1.0.118", features = ["rc", "derive"] }
+tokio = { version = "1.0.1", features = [
+    "sync",
+    "fs",
+    "rt",
+    "rt-multi-thread",
+    "io-util",
+    "macros",
+] }
+rand = "0.9.1"