feat(ocap-kernel): Implement hierarchical logging (#504)

Closes: #217 

This PR constitutes the majority of the lift for the referenced logging
ticket.

### `@metamask/logger`
- implements a protocol for serialized transfer of log entries over a
`@metamask/streams` `DuplexStream`
- adds the `injectStream` method to the `Logger` for subscribing to
logger notifications
- adds `makeArrayTransport` which returns a transport which appends log
entries to the supplied array argument
### `@MetaMask/ocap-kernel`
- The logger passed to the `Kernel` constructor is plumbed to
subcomponents all the way to the vat user code's console endowment and
logger power.
### `@ocap/kernel-test`
- no longer relies on intercepting `process.stdout` to assert expected
test vat operations
- utilizes logger tags for distinguishing different vat operations

Author: grypez

eslint.config.mjs

@@ -216,9 +216,12 @@ const config = createConfig([
   },
 
   {
-    files: ['packages/nodejs/test/workers/**/*'],
+    files: [
+      'packages/nodejs/test/workers/**/*',
+      'packages/logger/test/workers/**/*',
+    ],
     rules: {
-      // Test node worker files can resolve these imports, even if eslint cannot.
+      // Test worker files can resolve these imports, even if eslint cannot.
       'import-x/no-unresolved': 'off',
     },
   },

packages/extension/src/iframe.ts

@@ -32,6 +32,7 @@ async function main(): Promise<void> {
   new VatSupervisor({
     id: vatId,
     kernelStream,
+    logger: logger.subLogger(vatId),
   });
 
   logger.info('VatSupervisor initialized with vatId:', vatId);

packages/kernel-test/package.json

@@ -56,6 +56,7 @@
     "@metamask/kernel-shims": "workspace:^",
     "@metamask/kernel-store": "workspace:^",
     "@metamask/kernel-utils": "workspace:^",
+    "@metamask/logger": "workspace:^",
     "@metamask/ocap-kernel": "workspace:^",
     "@metamask/streams": "workspace:^",
     "@metamask/utils": "^11.4.0",