php-in-php: drop HashAlgos/HmacAlgos thin kernel fork — always JitVmHelperLink (#20652)

[PurHur]

Summary

• Drop isThinStandaloneAotMain → JitHashAlgosKernel thin registry ABI from StringHashAlgos / StringHashHmacAlgos; always JitVmHelperLink::ensureBridge → HashAlgosJitHelper (Rename php-in-php: drop isThinStandaloneAotMain libc fork from StringRename — always JitVmHelperLink + RenameJitHelper (re-#20028) #20603 / Fpow php-in-php: NestedJIT helper return ABI for double + __hashtable__* + string|false value-box (unblocks thin AOT always-helper) #20664 shape).
• Add phpc_hash_algos_kernel / phpc_hash_hmac_algos_kernel NestedJIT leaves (JitHashAlgosKernel::invoke*); helper returns array (not HashTable) so NestedJIT uses __hashtable__* instead of object TypeError.
• Shrink unit tests + spine/inventory updated. C/LLVM shrink: thin bridge forks deleted (~70 LOC from the two Builtin bridges); registry emit stays as NestedJIT leaf in ext/hash/.
• Sync spine footnotes to 5800/5800 (count-sync gate).

php-src reference

• ext/hash/hash.c — PHP_FUNCTION(hash_algos) / PHP_FUNCTION(hash_hmac_algos)

Verification (maintainer, local Docker)

./script/docker-exec.sh -- bash -lc 'source script/php-env.sh
vendor/bin/phpunit test/unit/StringHashAlgosRuntimeShrinkTest.php
# OK (2 tests, 19 assertions)
vendor/bin/phpunit test/unit/StringHashHmacAlgosRuntimeShrinkTest.php
# OK (2 tests, 17 assertions)
php bin/jit.php /tmp/h.php   # 60 44
php bin/vm.php /tmp/h.php    # 60 44
make bootstrap-selfhost-vm-driver-execute-probe
# OK
php script/bootstrap-inventory.php --check
# OK 5800/5800
php script/check-selfhost-spine-count-sync.php
# OK 5800/5800
'

AOT packing (still red — pre-existing)

With PHP_COMPILER_HELPER_RUNTIME_O=0, AOT hash_hmac_algos still prints assoc / no_sha256 while count===44 (same shape on master thin-kernel path before this PR). JIT/VM are green. Follow-up keeps #20652 open until AOT fixture is green.

Related: #20652 (bridge shrink landed here; AOT packing remains).

Test plan

• Shrink unit tests green
• JIT/VM hash_algos / hash_hmac_algos counts green
• bootstrap-selfhost-vm-driver-execute-probe green
• spine-count footnotes 5800/5800
• AOT hash_hmac_algos.phpt green (blocked — packing; tracked on php-in-php: drop isThinStandaloneAotMain kernel from StringHashAlgos/HmacAlgos — always JitVmHelperLink + HashAlgosJitHelper (re-#20050) #20652)