runtime: createRequire allowlist missing v8 (and audit the whole allowlist-vs-getBuiltinModule family) — pi wall #5 #6651

Wall #5 of the pi coding-agent bring-up (tracker #6564; prior: #6593, #6604, #6644, #6649 all fixed). With the four fixes applied, pi-native --help/--version die with:

Error: Perry createRequire() currently supports built-in modules only; package/file require('node:v8') is not supported under perry compile

Sites: __require("node:v8") at pi-bundle.mjs lines 179836 and 209270 (+ a require("v8") CJS shim at 182772). Node prints full usage / 0.0.0, rc=0.

This is the same gap family as #6644: v8 is missing from supported_require_builtin in crates/perry-runtime/src/module_require.rs, even though perry ships a real node_v8.rs module and process.rs getBuiltinModule already lists "v8".

Beyond adding v8: audit the whole family once — diff the createRequire allowlist against the getBuiltinModule list (and against the static-import module tables). Every builtin resolvable one way but not the others is a future wall of exactly this shape for some bundle; ESM bundles of CJS deps (the esbuild createRequire-banner pattern) funnel ALL builtin requires through createRequire, so its allowlist needs to be the superset. Walls #3 and #5 were both this bug with different module names.

Repro: HOME=$(mktemp -d) /Users/amlug/projects/perry/secret-tests/pi-target/dist/pi-native --help (binary has #6603+#6633+#6647+#6650 fixes; pi-native.pre6649 reproduces wall #4 for contrast); or minimal: ESM createRequire + require('node:v8').serialize fixture.