No watch-only (public-key-only) import mode

[ndii-dev]

app/auth/import.tsx only accepts a full secret key via StellarSdk.Keypair.fromSecret — there's no path to import just a public address to monitor balances/activity without custody, which is a common and materially safer onboarding option for users who primarily want visibility (e.g. a cold-storage holder checking balance from their phone). Add a watch-only mode that skips secureStorage.saveSecretKey entirely and clearly, persistently marks the account as non-signing everywhere in the UI.

Definition of done:

• Watch-only accounts flow through walletStore.ts with an explicit isWatchOnly flag
• Every signing-capable UI path (send, future contract calls) is disabled and clearly labeled for watch-only accounts, not just silently broken
• No SecureStore write occurs for a watch-only import

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Before opening a PR for this issue, read CONTRIBUTING.md.

This is not a starter-issue. The Definition of done above is the full
acceptance criteria, not a subset to sample from — a PR that addresses part
of it is an unfinished issue, not a smaller one. Your PR must include, in
the PR description itself:

• Root cause / design-decision rationale in your own words — not a restatement of this issue
• Every Definition of done bullet above addressed explicitly, with a one-line note on how
• Evidence the code actually runs: pasted test/build output, a screen recording or before/after screenshots for UI changes, or real (non-mocked) logs for network/contract-facing work
• New or updated tests included and shown passing (paste the output)
• Any adjacent/related behavior this issue calls out re-verified, not assumed unaffected

PRs missing these will be sent back before review, not reviewed and rejected — please do this up front.

[Ayinkx]

Hi i would like to work on this issue please assign to me
I can do it perfectly

[grantfox-oss]

🦊 GrantFox — @Ayinkx1 has been assigned to this issue as part of the Official Campaign | FWC26 campaign!

Next steps:

1. Open a Pull Request referencing this issue (e.g., Closes #30)
2. Your PR will be reviewed by the Orbit-Wal maintainers

Good luck! Track your progress on GrantFox.