fix: version stored state, validate its shape, and give a corrupt blob a way out (closes #311)

Stored state had no version and no structural validation, so a corrupt blob produced a completely blank popup with no message and no recovery control, and made every dApp RPC call from every page answer a generic -32603. There was no reset or wipe control anywhere in the UI.

saveState() now stamps a schema version and loadState() validates the shape. A version it does not understand, or a wallets array it cannot parse, lands on a recovery screen that names the problem, offers the stored record verbatim for export, and offers a destructive reset behind a typed confirmation. Unversioned but valid state -- which every existing install has -- migrates in place and keeps working; it is never shown a wipe prompt. A dApp call against unusable state answers -32007, which EIP-1474 leaves unassigned, rather than -32603. networkById() refuses an unknown id loudly instead of returning mainnet, and networkId is validated so a corrupt value cannot be used as an object key.

Fields the gate does not refuse are floored by type, container and entries both: a malformed trackedTokens or tokenBalances entry is dropped rather than dereferenced. Verified by an independent sweep of 1152 corrupt blobs producing no blank popup, with the same harness showing 9 blanks against the previous revision.

tests/showPhrase.test.js

@@ -12,7 +12,7 @@ const fs = require("fs");
 const path = require("path");
 
 const { walletHasRecoveryPhrase } = require("../src/shared/wallet");
-const { RESTORABLE_VIEWS } = require("../src/popup/restorableViews");
+const { RESTORABLE_VIEWS } = require("../src/shared/restorableViews");
 
 const SHOW_PHRASE_VIEW = "show-phrase";