fix(frontend): normalize API and wallet errors safely

[isaacsamual994-lang]

Description

Normalizes API and wallet failures into a small safe error shape so raw provider responses, server details, wallet addresses, and token-like values are not surfaced to users. The normalized policy also carries explicit retryability and a validated correlation/request identifier for protected diagnostics.

Motivation

Issue #283 calls out two related problems: provider/server details can leak sensitive account data into user-facing errors, and callers can make unsafe retry decisions when failures are not classified consistently.

Changes Made

• Add a centralized error normalizer with stable safe codes, retryability, safe user messages, and validated correlation IDs.
• Keep raw provider messages/payloads out of the normalized/user-facing shape by default.
• Distinguish wallet rejection/cancellation from retryable timeout, rate-limit, network, and 5xx failures.
• Use the safe policy in wallet connection, transfer loading, and send-money submission paths.
• Withhold the existing transfer retry action while a non-retryable error is displayed; keep it available for retryable failures.
• Add regression coverage for malformed errors, sensitive-value redaction, wallet rejection, timeout/rate-limit/5xx classification, correlation handling, submit failures, and retry policy.

Testing

• 24 Vitest files / 135 tests passed locally using the repository's integration/unit/Lighthouse-config test paths with thread workers (the default fork pool is blocked by the Charlotte sandbox's process permissions).
• npm run build passed.
• git diff --check passed.
• ESLint passes on the files changed by this PR. The repository-wide lint command currently reports 9 pre-existing errors in files untouched by this change.
• No visual/layout changes, so screenshots and a Lighthouse UI rerun are not applicable here.

Screenshots (if applicable)

Not applicable; this changes error handling/messages and retry policy without layout or styling changes.

Checklist

• Tests pass locally
• Code follows style guidelines for the changed files
• Documentation update not required
• No breaking changes
• Lighthouse UI check not applicable (no layout/style changes)

Closes #283

[isaacsamual994-lang]

@arisu6804 #283 is implemented and ready for review in this PR. The branch is conflict-free and the local test/build validation is included above. GitHub is currently showing two workflows awaiting maintainer approval; when you have a chance, could you please approve those runs and review the change? Thanks!