fix(wall): hold the PCP holder in a Global, not a Persistent

[szegedi]

Review follow-up on #385 (@nsavoire's two nits, both landed after merge).

Persistent -> Global

v8::Persistent has no destruction behaviour — the handle leaks unless every path clears it by hand. v8::Global releases it in its own destructor, and is what every other handle in this file already uses: ContextPtr, cpedKey_, wrapObjectTemplate_, jsArray_. The Persistent I introduced in #385 was the odd one out.

Nothing was actually leaking, since ~PersistentContextPtr always reset the handle explicitly — but relying on that is exactly the footgun the docs warn about. With Global the release becomes structural, so the explicit Reset() goes away with it.

Worth recording why the manual handle existed at all: before #261 removed instance reuse, PersistentContextPtr recycled itself through a freelist and needed ClearWeak/Reset to unregister and re-register the same object. With reuse gone, a handle lives exactly as long as its PCP, so there's nothing left for Persistent's manual semantics to buy.

[github-actions]

Overall package size

Self size: 2.46 MB
Deduped: 3.16 MB
No deduping: 3.16 MB

Dependency sizes

| name | version | self size | total size | |------|---------|-----------|------------| | pprof-format | 2.3.0 | 503.97 kB | 503.97 kB | | source-map | 0.8.0 | 185.66 kB | 185.66 kB | | node-gyp-build | 4.8.4 | 13.86 kB | 13.86 kB |

_{🤖 This report was automatically generated by heaviest-objects-in-the-universe}

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