ABI: implement rooted native value containers

[chrisbbreuer]

Parent: #140
Profile parents: #163 and #164

Implement the five shared native rooted-value container operations:

• MarkedArgumentBuffer__run
• MarkedArgumentBuffer__append
• JSCommonJSExtensions__appendFunction
• JSCommonJSExtensions__setFunction
• JSCommonJSExtensions__swapRemove

Acceptance:

• Construct the opaque marked argument buffer only for the synchronous callback extent.
• Root every appended cell across precise collection during the callback; accept immediates and reject cross-VM cells safely.
• Remove all temporary roots on normal return and preserve cleanup under callback re-entry.
• Keep the CommonJS function registry per selected realm with exact append index, set replacement, and swap-remove return semantics.
• Trace registered functions until removal and release removed values without disturbing sibling realms.
• Make invalid indices, null callbacks, allocation failure, and pending exceptions deterministic and failure-atomic.
• Add focused GC tests and the real 5-symbol consumer fixture, regenerate both inventories, and update README/profile docs.

[chrisbbreuer]

Complete on main through 3d87a83b (implementation 37df3f70).

Evidence:

• focused precise-GC unit gate: 3/3 passed, zero leaks;
• Home audit: 179/431 implemented, 252 pending;
• Bun core audit: 173/421 implemented, 248 pending;
• real combined consumer fixture: 178/178 linked and runtime-exercised;
• public classification audit: 117/117 public, 19 extensions, 183 private/support exports.

The tests force full collection inside a marked-buffer callback, verify callback-extent root cleanup and cross-VM rejection, and cover per-realm CommonJS append/set/swap-remove indices, replacement, removal, VM isolation, invalid inputs, and first-pending-exception preservation. README.md and all ABI/API/Home docs publish the new counts and semantics.