nx_bundle_gen.nx

nx_bundle_gen.nx -- pure-NishiLang shard-bundle generator. Walks specs/algo_registry/ to collect shape-driven primitives, then emits runtime/_bundle_shard_<i>.nx files where each shard inlines renamed copies of multiple primitives' test.nx, plus a master main() that invokes every test_<nx>() and emits PASS/FAIL via sys_write. Replaces sed-per-primitive in bash (which cost ~139s wall for 1192 primitives via 1192 subshells). Pure NishiLang means substrate self- generates its own bundles -- aligns with the "no host tools for own bookkeeping" directive. Rewriting rules per inlined test.nx: 1. Strip lines starting with `import ` (bundle re-emits the shared imports at the top once) 2. Rename `func main() -> nx_int` -> `func test_<nx>() -> nx_int` and `func main() -> i64` -> `func test_<nx>() -> nx_int` 3. Replace `__syscall(93, N, 0, 0, 0, 0, 0)` (process exit syscall) with plain `N` so failure propagates to the bundle's master main