Add kv-wasm: the core compiled to WebAssembly for the web vault

New crate crates/kv-wasm runs the same crypto, item model and sync engine in the browser:
- WebStore: in-memory replica of kv-store's Store, each changed entry written to IndexedDB
  (ciphertext only) before the JS call resolves.
- Device key: non-extractable WebCrypto ECDSA P-256 key in IndexedDB (raw r||s signatures).
- WebCore mirrors kv-ffi's VaultCore; wasm-bindgen surface in camelCase with TypeScript types,
  plus a Web Worker wrapper (connectVault) so Argon2id never blocks the page.
- Tests: Chrome (IndexedDB, WebCrypto, RFC 9421 verify), shared envelope fixtures both ways
  with kv-ffi, native sync with kv-ffi via the test server, Node smoke of the built package.

Small changes to shared crates so they build for wasm32:
- kv-store: SqliteStore moved to a native-only module.
- kv-sync: rustls/pinning/tokio native only (fetch on wasm); DeviceSigner::sign_async (default
  wraps sign) used by ApiClient; unix_now() instead of SystemTime/now_utc.
- kv-model: Public Suffix List behind a default `psl` feature (kv-ffi keeps it; the web build
  drops ~0.9 MB of code and matches same-host only).
- wasm-release profile (opt-level z, Argon2 at 3) and a wasm CI job.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

Cargo.lock

@@ -202,6 +202,17 @@ dependencies = [
  "tokio",
 ]
 
+[[package]]
+name = "async-trait"
+version = "0.1.92"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "82f6aeea286b8eb4dd3431a1be1b59d290ace00f5bfd8e2a159bc2a05e2c1667"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn 3.0.9",
+]
+
 [[package]]
 name = "atomic-waker"
 version = "1.1.2"
@@ -337,6 +348,12 @@ dependencies = [
  "thiserror 1.0.69",
 ]
 
+[[package]]
+name = "cast"
+version = "0.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "37b2a672a2cb129a2e41c10b1224bb368f9f37a2b16b612598138befd7b37eb5"
+
 [[package]]
 name = "cc"
 version = "1.8.0"
@@ -1440,6 +1457,7 @@ dependencies = [
  "base64 0.22.1",
  "blake3",
  "ciborium",
+ "js-sys",
  "kv-crypto",
  "kv-model",
  "kv-proto",
@@ -1467,6 +1485,35 @@ dependencies = [
  "zeroize",
 ]
 
+[[package]]
+name = "kv-wasm"
+version = "0.1.0"
+dependencies = [
+ "getrandom 0.2.17",
+ "js-sys",
+ "kv-crypto",
+ "kv-ffi",
+ "kv-import",
+ "kv-model",
+ "kv-proto",
+ "kv-store",
+ "kv-sync",
+ "serde",
+ "serde-wasm-bindgen",
+ "serde_bytes",
+ "serde_json",
+ "sha2",
+ "tempfile",
+ "thiserror 2.0.21",
+ "tokio",
+ "uuid",
+ "wasm-bindgen",
+ "wasm-bindgen-futures",
+ "wasm-bindgen-test",
+ "web-sys",
+ "zeroize",
+]
+
 [[package]]
 name = "lazy_static"
 version = "1.5.1"
@@ -1479,6 +1526,12 @@ version = "0.2.190"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "ce5d3ddc6d3fa000eb1536d85e147bfe31aacaba692ed6a876f95cb7c855be78"
 
+[[package]]
+name = "libm"
+version = "0.2.16"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b6d2cec3eae94f9f509c767b45932f1ada8350c4bdb85af2fcab4a3c14807981"
+
 [[package]]
 name = "libsqlite3-sys"
 version = "0.30.1"
@@ -1530,6 +1583,16 @@ dependencies = [
  "unicase",
 ]
 
+[[package]]
+name = "minicov"
+version = "0.3.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4869b6a491569605d66d3952bcdf03df789e5b536e5f0cf7758a7f08a55ae24d"
+dependencies = [
+ "cc",
+ "walkdir",
+]
+
 [[package]]
 name = "minimal-lexical"
 version = "0.2.1"
@@ -1579,12 +1642,31 @@ dependencies = [
  "minimal-lexical",
 ]
 
+[[package]]
+name = "nu-ansi-term"
+version = "0.50.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7957b9740744892f114936ab4a57b3f487491bbeafaf8083688b16841a4240e5"
+dependencies = [
+ "windows-sys 0.61.2",
+]
+
 [[package]]
 name = "num-conv"
 version = "0.2.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "521739c6d2bac4aa25192232afe6841231376b2b26d4d9fae5ecf8ca5772e441"
 
+[[package]]
+name = "num-traits"
+version = "0.2.19"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "071dfc062690e90b734c0b2273ce72ad0ffa95f0c74596bc250dcfd960262841"
+dependencies = [
+ "autocfg",
+ "libm",
+]
+
 [[package]]
 name = "num_cpus"
 version = "1.17.0"
@@ -1607,6 +1689,12 @@ version = "1.70.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "384b8ab6d37215f3c5301a95a4accb5d64aa607f1fcb26a11b5303878451b4fe"
 
+[[package]]
+name = "oorandom"
+version = "11.1.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d6790f58c7ff633d8771f42965289203411a5e5c68388703c06e14f24770b41e"
+
 [[package]]
 name = "opaque-debug"
 version = "0.3.1"
@@ -2028,6 +2116,15 @@ version = "1.0.23"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9774ba4a74de5f7b1c1451ed6cd5285a32eddb5cccb8cc655a4e50009e06477f"
 
+[[package]]
+name = "same-file"
+version = "1.0.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "93fc1dc3aaa9bfed95e02e6eadabb4baf7e3078b0bd1b4d7b6b0b68378900502"
+dependencies = [
+ "winapi-util",
+]
+
 [[package]]
 name = "scroll"
 version = "0.12.0"
@@ -2082,6 +2179,27 @@ dependencies = [
  "serde_derive",
 ]
 
+[[package]]
+name = "serde-wasm-bindgen"
+version = "0.6.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8302e169f0eddcc139c70f139d19d6467353af16f9fce27e8c30158036a1e16b"
+dependencies = [
+ "js-sys",
+ "serde",
+ "wasm-bindgen",
+]
+
+[[package]]
+name = "serde_bytes"
+version = "0.11.19"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a5d440709e79d88e51ac01c4b72fc6cb7314017bb7da9eeff678aa94c10e3ea8"
+dependencies = [
+ "serde",
+ "serde_core",
+]
+
 [[package]]
 name = "serde_core"
 version = "1.0.229"
@@ -2760,6 +2878,16 @@ dependencies = [
  "zeroize",
 ]
 
+[[package]]
+name = "walkdir"
+version = "2.5.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "29790946404f91d9c5d06f9874efddea1dc06c5efe94541a7d6863108e3a5e4b"
+dependencies = [
+ "same-file",
+ "winapi-util",
+]
+
 [[package]]
 name = "want"
 version = "0.3.2"
@@ -2831,6 +2959,45 @@ dependencies = [
  "unicode-ident",
 ]
 
+[[package]]
+name = "wasm-bindgen-test"
+version = "0.3.79"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ae7499dfd45780a0a91d7ee6bb9ac51970a4479a41a89da443fdda5a39547d42"
+dependencies = [
+ "async-trait",
+ "cast",
+ "js-sys",
+ "libm",
+ "minicov",
+ "nu-ansi-term",
+ "num-traits",
+ "oorandom",
+ "serde",
+ "serde_json",
+ "wasm-bindgen",
+ "wasm-bindgen-futures",
+ "wasm-bindgen-test-macro",
+ "wasm-bindgen-test-shared",
+]
+
+[[package]]
+name = "wasm-bindgen-test-macro"
+version = "0.3.79"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3b84b5ac638bfb168196a1a461fcc8f46a294a18b1b6be52133b4e0db122cc9f"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn 3.0.9",
+]
+
+[[package]]
+name = "wasm-bindgen-test-shared"
+version = "0.2.129"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4f692aa943ccd88363733b77063f32cfed5bc6cbea8e6e8b251b302f881606fe"
+
 [[package]]
 name = "web-sys"
 version = "0.3.106"
@@ -2868,6 +3035,15 @@ dependencies = [
  "nom",
 ]
 
+[[package]]
+name = "winapi-util"
+version = "0.1.11"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c2a7b1c03c876122aa43f3020e6c3c3ee5c05081c9a00739faf7503aeba10d22"
+dependencies = [
+ "windows-sys 0.61.2",
+]
+
 [[package]]
 name = "windows-link"
 version = "0.2.1"