chore(workspace): gate dead-code with knip production mode

Turn on production-mode knip plus an autofix run in pre-commit and the
`pnpm dead-code` script, document the `/** @internal */` convention for
test-only exports in AGENTS.md, annotate test-only exports across the
CLI with that JSDoc, and drop dead exports/wrappers the new gate
surfaced (e.g. `cli-project.ts`, `lookerRuntimeSourceToFileAdapterSource`,
`createLocalScanEnrichmentProvidersFromConfig`,
`PGLITE_OWNER_PROCESS_BACKEND_CAPABILITIES`, stale type re-exports).
Replace the loose `ignoreIssues` allowlist in `knip.json` with explicit
production entries so cross-package barrel leaks are caught.

packages/cli/src/io/logger.ts

@@ -14,6 +14,7 @@ function writeLine(io: KtxCliIo, message: string): void {
   io.stderr.write(message.endsWith('\n') ? message : `${message}\n`);
 }
 
+/** @internal */
 export function createNoopOperationalLogger(): KtxOperationalLogger {
   return {
     log: () => undefined,