feat: POSIX/P2P roadmap — multisig shape, socket bridge, bin index, docs

- Unify pear.multisig.json validation via bare-os-protocol + kernel boot fragment
- Socket bridge: SCM_RIGHTS path, ancillary handling, TCP half-close/shutdown how,
  connect tcpRecvQueue + poll/recv EOF and EPIPE-shaped errors
- Bin manifest / Hyperbee hints schema 2 + namesDigest; batch-write invalidation
- Host booter structured logging; BOOT_PERF_DETAIL bare_stdlib_merge_ns timing
- Wasm kernel optional syscall imports; security_posture rotation hints schema 2
- Shell errexit inside compound bodies; expand getconf/_SC_* and bareOsGetconfSysconf
- Subprocess bridge snapshot timeoutPolicy; blind-relay protomux backpressure tests
- Pear updater minimal delegate example + verify-pear scan; holepunch drift repos
- Refresh handbook, kernel-image, syscall-socket-contract, posix matrix, PEAR-RUN

Rebuild coreutils/bundles; bundle kernel; keep seeder/kernel parity.

kernel/lib/bare/shell-completion.json

@@ -1,6 +1,6 @@
 {
   "schema": 1,
-  "atMs": 1775367918774,
+  "atMs": 1775369250127,
   "commands": [
     "arch",
     "awk",