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.

TODO.md

@@ -57,6 +57,46 @@ but the review is broader than any of them.
   `Token Out` now reads `Unknown (not named in the calldata)` and
   `Min. received` falls to the base-unit refusal from
   [#340](https://git.eeqj.de/sneak/AutistMask/issues/340).
+
+- 2026-08-23: The stored profile carries a schema version, and a record the
+  wallet cannot read produces a screen instead of a blank popup
+  ([#311](https://git.eeqj.de/sneak/AutistMask/issues/311)). `saveState()` and
+  `updateState()` both stamp `STATE_SCHEMA_VERSION`
+  (`src/shared/stateSchema.js`), and every read goes through
+  `assertStateUsable()` on the raw bytes before normalization gets a chance to
+  paper over them. Version 1 is the shape that shipped unversioned, so the
+  profile every existing install holds loads normally and is migrated in place
+  by being stamped on the first write — an upgrade shows nobody a wipe prompt
+  for a wallet that is fine. A record this build cannot vouch for is refused
+  instead: not normalized, not written back, not half-loaded. The popup shows
+  the new StateRecovery screen, which names the problem, exports the raw record
+  verbatim into the page (and downloads it where the browser allows), and offers
+  an erase behind a typed `ERASE MY WALLET` — both controls, because an export
+  with no reset leaves the user stuck and a reset with no export destroys the
+  only copy of possibly recoverable key material. The background refuses the
+  same record and answers dApps `-32007` — a code EIP-1474 leaves unassigned,
+  unlike `-32000`..`-32006` — with a message saying the saved data cannot be
+  read and that nothing was signed or sent, rather than the generic `-32603`
+  that every request used to get. Fields the gate deliberately does not check
+  produced the same blank popup on their own: `trackedTokens` and
+  `activeAddress` were floored on truthiness rather than on type, and
+  `trackedTokens`' ENTRIES and each address's `tokenBalances` were not floored
+  at all — `[1, 2]` is a list, and the dereference is `t.address.toLowerCase()`
+  one level below the container. All of them are type-checked now, entries
+  included, and the header of `src/shared/stateSchema.js` lists which fields of
+  the record get a type check and which get a `saved.x || default` or a verbatim
+  passthrough, rather than asserting a rule the module does not follow.
+  `networkById()` now throws on an id it does not know instead of quietly
+  answering mainnet, and the gate's key tests are all own-property tests:
+  `networkId` is an object key into `networkEndpoints`, so an unvalidated
+  `"__proto__"` used to set that map's prototype and drop the user's endpoint
+  silently. The three corrupt blobs from the issue drive the real popup entry
+  point in `tests/stateRecovery.test.js` and the real worker in
+  `tests/stateUnusableRpc.test.js`; each rendered nothing at all and answered
+  `-32603` before this. `src/popup/restorableViews.js` moved to
+  `src/shared/restorableViews.js`, since `persistedState.js` requires it and
+  that module is in the background bundle.
+
 - 2026-08-23: The background no longer reads or writes the shared `state`
   singleton ([#324](https://git.eeqj.de/sneak/AutistMask/issues/324)), which
   also closes the cold-worker wrong-chain send