Keep wallet scan metadata, caches and write acknowledgements consistent

[a-shannon]

Changing a tracked box's scan associations preserves its inclusion and spending metadata. Payment-association changes affect ERG and token balances only while the box is unspent. Registry writes propagate their actual result to callers, including the actor's AddBox response; preparing a write no longer exposes uncommitted metadata through the cache, and affected entries reload from persistence after either outcome. When a previously registered box is created and spent in the current block, current-block metadata takes precedence and superseded indexes are removed.

Head 2b529f7366f4c2cc146278d8f2266db95d289ef0 retains both registry corrections and all four owning files. Review #2514 first, then the pinned registry correction and maturity composition. The composition preserves the maturity-removal bag before folding old-output index cleanup and retains rejected-write/successful-retry contracts under both history-retention settings. GitHub's upstream-master diff remains cumulative until the prerequisites merge.

The maturity-parent refresh incorporates the real #2514 parent, including existing shared prerequisites: D, owned by #2535, establishes a settled seed and isolated mining; X, owned by #2549, wakes cached block sections after headers; and G, owned by #2511, supplies synchronization continuation/cache/download corrections. These retain their own review and integration dependencies; the registry files are unchanged by the refresh.

The final two-file diagnostic increment reuses exact K, owned by #2511 on #2535's shared H observer. It reports ForkResolution phases and bounded node observations while retaining the fixed target, independent per-node acceptance and fifteen-minute deadline. The shared increments can be reviewed once; the diagnostic addition changes no production code.

Historical registry validation passed all 68 WalletScanLogicSpec, WalletRegistrySpec and WalletRegistryWriteResultSpec cases, covering metadata, spent-payment balances, write failures/retries, cache/index agreement, actor acknowledgements and both history settings. The actual refreshed composition passed 133 tests: synchronization/header-body joins 49, WalletRegistrySpec 27, WalletRegistryWriteResultSpec 24 and shared observer/isolation cases 33. The subsequent K composition passed normal integration-test compilation and 37/37 observer/diagnostic cases. Unchanged source evidence is reused; these focused runs did not execute Docker. Independent composition review found no blockers.

At previous public head 459f6bbd5d80f31dd55a3eb240377339a6c3622f, CI passed seven of eight jobs and 20/22 IT cases, with DeepRollBack and ForkResolution timeouts. Their exclusive causes were not established. New-head native CI must test the combined behavior and collect the added diagnostics; no successful Docker result is claimed here. Follow #2533 for current results.