cargo.build, the WASI test runner, the console, and core.notify ordering

- cargo.build (native): one source copy, tests under WASI, release
  build to /state/cargo/builds/<n>/, process groups killed on cancel.
  The host writes the SDK copy to /plugins/cargo/sdk/ at start.
- sausage test-runner: one instance per test, in parallel, with its own
  mount table (empty world, package folder at its path); answers
  core.lock, core.unlock, core.notify, core.log.
- The console: rustyline, notifications while typing, ls/cat through the
  process view, methods, ps, log, activate, revert, stop, kill.
- core.notify on stdout is handled in order, before the response.

Cargo.lock

@@ -11,6 +11,16 @@ dependencies = [
  "gimli",
 ]
 
+[[package]]
+name = "agent"
+version = "0.1.0"
+dependencies = [
+ "sausage-plugin",
+ "serde",
+ "serde_json",
+ "wstd",
+]
+
 [[package]]
 name = "allocator-api2"
 version = "0.2.21"
@@ -310,6 +320,15 @@ version = "1.1.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "1c133bc6a41be0d194c306b5506d15e6feeea7b1d6604bd3f8310dfb2ca96486"
 
+[[package]]
+name = "clipboard-win"
+version = "5.4.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bde03770d3df201d4fb868f2c9c59e66a3e4e2bd06692a0fe701e7103c7e84d4"
+dependencies = [
+ "error-code",
+]
+
 [[package]]
 name = "cobs"
 version = "0.3.0"
@@ -637,6 +656,12 @@ dependencies = [
  "simdutf8",
 ]
 
+[[package]]
+name = "endian-type"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "869b0adbda23651a9c5c0c3d270aac9fcb52e8622a8f2b17e57802d7791962f2"
+
 [[package]]
 name = "equivalent"
 version = "1.0.3"
@@ -653,6 +678,12 @@ dependencies = [
  "windows-sys 0.61.2",
 ]
 
+[[package]]
+name = "error-code"
+version = "3.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0b5343afd4a8365a643ac588dab4cf234a190c7f6c88c9f6dd6ffe00837661b7"
+
 [[package]]
 name = "fallible-iterator"
 version = "0.3.0"
@@ -957,6 +988,15 @@ version = "0.5.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "2304e00983f87ffb38b55b444b5e3b60a884b5d30c0fca7d82fe33449bbe55ea"
 
+[[package]]
+name = "home"
+version = "0.5.12"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cc627f471c528ff0c4a49e1d5e60450c8f6461dd6d10ba9dcd3a61d3dff7728d"
+dependencies = [
+ "windows-sys 0.61.2",
+]
+
 [[package]]
 name = "http"
 version = "1.5.0"
@@ -1024,6 +1064,20 @@ dependencies = [
  "want",
 ]
 
+[[package]]
+name = "hyper-util"
+version = "0.1.21"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ddc03d96684f9226b8a787cdb71488417b53ab5ea8fdb1dac946cb9431cc8bff"
+dependencies = [
+ "bytes",
+ "http",
+ "http-body",
+ "hyper",
+ "pin-project-lite",
+ "tokio",
+]
+
 [[package]]
 name = "icu_collections"
 version = "2.3.0"
@@ -1429,6 +1483,27 @@ version = "1.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "743fb55ba31b18fb1ecef6bdc9aa2743314978ac084044301a7eee33fb99a20d"
 
+[[package]]
+name = "nibble_vec"
+version = "0.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "77a5d83df9f36fe23f0c3648c6bbb8b0298bb5f1939c8f2704431371f4b84d43"
+dependencies = [
+ "smallvec",
+]
+
+[[package]]
+name = "nix"
+version = "0.31.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cf20d2fde8ff38632c426f1165ed7436270b44f199fc55284c38276f9db47c3d"
+dependencies = [
+ "bitflags",
+ "cfg-if",
+ "cfg_aliases",
+ "libc",
+]
+
 [[package]]
 name = "notify"
 version = "8.2.0"
@@ -1659,6 +1734,16 @@ version = "6.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "f8dcc9c7d52a811697d2151c701e0d08956f92b0e24136cf4cf27b57a6a0d9bf"
 
+[[package]]
+name = "radix_trie"
+version = "0.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3b4431027dcd37fc2a73ef740b5f233aa805897935b8bce0195e41bbf9a3289a"
+dependencies = [
+ "endian-type",
+ "nibble_vec",
+]
+
 [[package]]
 name = "rand"
 version = "0.10.3"
@@ -1903,6 +1988,26 @@ dependencies = [
  "wait-timeout",
 ]
 
+[[package]]
+name = "rustyline"
+version = "19.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "56e1d6bd81c2d5feafd2419138df9183c45a10a492c4e873b8b0acb8eb2b549e"
+dependencies = [
+ "bitflags",
+ "clipboard-win",
+ "home",
+ "libc",
+ "log",
+ "memchr",
+ "nix",
+ "radix_trie",
+ "unicode-segmentation",
+ "unicode-width",
+ "utf8parse",
+ "windows-sys 0.61.2",
+]
+
 [[package]]
 name = "same-file"
 version = "1.0.6"
@@ -1921,9 +2026,13 @@ dependencies = [
  "clap",
  "http",
  "http-body-util",
+ "hyper",
+ "hyper-util",
  "include_dir",
+ "nix",
  "notify",
  "rusqlite",
+ "rustyline",
  "sausage-interface",
  "sausage-vfs",
  "serde",
@@ -2573,6 +2682,12 @@ version = "1.0.27"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "a2c754d6c33795a1c324727428e5a7dedb5b06195f9890bdbcba760d3e246563"
 
+[[package]]
+name = "unicode-segmentation"
+version = "1.13.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c6f5d3c3b1bf09027a88a6bc961fc00497d651009560b5463668dc81b0fa87a8"
+
 [[package]]
 name = "unicode-width"
 version = "0.2.2"