Home ABI: alias unchanged private profile at revision 38702f9e

Parent: #163 Depends on: #168

Home advanced to 38702f9e43b3aecbee7d5b7aa48cc66d41cabde7 for ts-checker work. The complete packages/runtime/src/jsc diff from the already-supported revision is empty, but the revision must be accepted only through an explicit audited alias.

Acceptance:

• Add a distinct home-private-38702f9e alias manifest tied to the immutable home-private-7ed99c02 denominator.
• Prove all 58 private-ABI source hashes are unchanged.
• Prove all 448 declarations, locations, classifications, signatures, and calling conventions are unchanged.
• Report zero added/removed/changed declarations and zero convention changes.
• Reject every unknown revision/profile ID.
• Verify the live revision through the compile-link-runtime Home gate.
• Update the parent map, ABI docs, integration guide, README, and reproduction commands.

Completed on main in 17e6532; documentation followed in 7f9d2b5.

Evidence:

• home-private-38702f9e is a distinct manifest tied to the immutable 7ed99c02 source contract;
• live audit at 38702f9e43b3aecbee7d5b7aa48cc66d41cabde7 verifies 58/58 hashes and 448/448 declarations, with zero additions, removals, signature changes, calling-convention changes, duplicates, or unclassified symbols;
• the same live checkout is rejected when requested as the older home-private-5e829ad4 alias;
• zig build test-home-private-abi -Dhome-private-abi-profile=home-private-38702f9e -Dhome-source-root=/Users/chris/Code/Home/lang passes the audit and 9/9 runtime value-shim fixture;
• README and ABI/Home integration docs now list all three exact supported revisions and the current reproduction command.