fix: derive hasWallet from the wallet list on load (closes #195)

loadState() took hasWallet straight from storage, so any profile persisted
with the flag out of step with wallets stayed broken on every subsequent
load rather than only until the next write. The flag is now derived from
wallets.length at load time.

The only consumer is the popup's welcome-vs-wallet-list gate in
src/popup/index.js; the only writers set it true alongside an added
wallet. Nothing reads it expecting it to differ from wallets.length, so
deriving is safe and needs no write-back on load.

TODO.md

@@ -44,6 +44,10 @@ undefined identifiers, which is how
 
 # Completed Steps
 
+- 2026-08-11: `loadState()` now derives `hasWallet` from the wallet list instead
+  of trusting the persisted flag, so a profile already saved inconsistent no
+  longer stays broken on every load
+  ([#195](https://git.eeqj.de/sneak/AutistMask/issues/195)).
 - 2026-08-11: Wallet deletion repairs its own state — `hasWallet` follows the
   remaining wallets, the selection only moves when it was deleted, and the
   active-address change is broadcast to connected sites