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.

src/popup/views/helpers.js

@@ -45,6 +45,11 @@ const VIEWS = [
     "approve-sign",
     "export-privkey",
     "show-phrase",
+    // Shown by src/popup/views/stateRecovery.js when the stored profile
+    // cannot be read. It is never reached through showView() — by then the
+    // state singleton this file writes on every navigation refuses to be read
+    // — but it is listed so that every view-hiding loop covers it.
+    "state-recovery",
 ];
 
 // Cleanup callbacks for views that hold a secret in the DOM. The view