Complete top-level Bun cli/run corpus compatibility

Tracks the next Bun corpus compatibility tranche from #66.\n\nScope:\n- workspace filter diagnostics and partial success with malformed package manifests\n- preload-first failure ordering and missing-preload diagnostics\n- missing/empty package-script behavior\n- panic child termination with trap-signal listeners\n- system-shell interpreter isolation from node_modules/.bin\n- binary transpiler-cache module-record validation\n- --tsconfig-override path resolution layouts\n- plain --workspaces script fan-out and no-match behavior\n\nExact validation targets:\n- filter-workspace.test.ts: 55 pass / 0 fail / 0 unsupported / 0 todo\n- preload-test.test.js: 2 / 0 / 0 / 3 upstream todo\n- run_command.test.ts: 2 / 0 / 0 / 1 upstream todo\n- run-crash-handler.test.ts: 6 / 0 / 0 / 1 upstream todo\n- run-shell.test.ts: 3 / 0 / 0 / 0\n- transpiler-cache.test.ts: 11 / 0 / 0 / 0\n- tsconfig-override.test.ts: 6 / 0 / 0 / 0\n- workspaces.test.ts: 3 / 0 / 0 / 0\n- every other top-level cli/run test file exact-green\n- full loopback-enabled home_test gate: exit 0\n\nParent: #66

Completed and published directly to main in 7526421 (feat(runtime): complete bun run corpus compatibility).\n\nExact validation:\n- filter-workspace.test.ts: 55 pass / 0 fail / 0 unsupported / 0 todo\n- preload-test.test.js: 2 / 0 / 0 / 3 upstream todo\n- run_command.test.ts: 2 / 0 / 0 / 1 upstream todo\n- run-crash-handler.test.ts: 6 / 0 / 0 / 1 upstream todo\n- run-shell.test.ts: 3 / 0 / 0 / 0\n- transpiler-cache.test.ts: 11 / 0 / 0 / 0\n- tsconfig-override.test.ts: 6 / 0 / 0 / 0\n- workspaces.test.ts: 3 / 0 / 0 / 0\n- Every other top-level cli/run test file was rechecked exact-green\n- Full loopback-enabled home_test gate completed with exit 0\n\nParent tracking remains #66.