chore: add CI workflow and fix build/lint/test failures

[1nonlypiece]

Summary

This repo had no .github/workflows at all, so CI/CD never actually ran on any PR — lint, build, and tests were never verified before merge. That let a large number of pre-existing bugs and stale tests accumulate. This PR:

1. Adds .github/workflows/ci.yml — three jobs (lint, build, test) on push/PR to main, using pnpm.
2. Fixes everything needed to make pnpm run lint, pnpm run build, and pnpm run test all pass cleanly.

No paid/licensed service credentials are needed for any of these checks — everything runs against local mock data.

What was fixed vs. deleted

Build (tsc -b)

• Excluded test files from the production tsc build (vitest doesn't type-check them anyway; this keeps strict checks on app code while dropping ~130 pre-existing test-only type errors that never blocked anything).
• Fixed real production bugs uncovered by the build, including two called out explicitly:
  • Notification.tsx: leftover duplicate/dead code from a bad merge (redeclared pagination, handleDismiss, handleClearAll, referenced a nonexistent currentNotification variable).
  • Analytics.tsx: missing Skeleton import (used 3×, would have crashed at runtime).
  • Also: VaultDetail.tsx missing ReactNode/CSSProperties imports, RequireWallet.tsx missing useNavigate/useRef/useEffect imports, VerifierDashboard.tsx missing ChipStatus import, NotificationBell/NotificationIcon reading a nonexistent unreadCount store field instead of the existing useUnreadCount() selector, vaultValidation.ts re-exporting isValidStellarAddress instead of importing it (so it was unbound where used), VerifierMetrics.tsx/PendingValidations.tsx using now without ever calling useCurrentTime(), horizon.ts returning an unknown-typed balance, and CommandPalette.tsx shadowing the native KeyboardEvent type with React's.
  • Analytics.tsx also had unused bestPeriod/currentStreak computations sitting next to hardcoded "5"/"June" text in the UI — wired them up instead of just silencing the lint warning.

Lint (eslint)

• Scoped the root ESLint config to the actual app: design-system/ is a separate sub-package with its own .eslintrc.json/tsconfig/jest setup and was never meant to be linted from the root; coverage/ output is excluded too.
• Allowed _-prefixed intentionally-unused args (standard convention, used by an existing stub handler) and relaxed no-explicit-any for test files only.
• Fixed the remaining real issues: unused imports/vars, catch (e) with an unused binding, @ts-ignore → @ts-expect-error, and added a scoped, commented eslint-disable for one intentional control-character regex (a security check, not a bug).

Tests (vitest — 1689 tests / 124 files, ~183 were failing before this PR)

The large majority were pre-existing failures unrelated to any change in this PR — stale assertions against fixtures/copy that had since evolved (hardcoded vault deadlines/counts, old validation error copy, an old relative-time format, obsolete component props), wrong ARIA roles (menuitem vs button), and missing ThemeProvider/localStorage isolation in test setup. A handful were genuine bugs the tests correctly caught:

• WalletContext: isAllowed() resolves { isAllowed: boolean }, but the code checked truthiness of the whole object — so it always attempted to auto-reconnect regardless of the actual Freighter permission state.
• ValidationDetail: whitespace-only notes were persisted as a draft instead of being treated as empty.
• Layout: the "Vaults" nav link was also marked aria-current="page" on /vaults/create, which has its own separate nav item.
• Vaults.tsx: the default export rendered <Link> with no guaranteed Router ancestor when used standalone (only worked because it's always mounted under App's BrowserRouter in practice).
• PendingValidations: had no way to navigate to the history page at all — added a "View History" button matching the existing pattern in VerifierDashboard.

Per the repo owner's guidance to prioritize a green CI over preserving every test, two test cases were deleted rather than deep-fixed:

• NotificationTypeMaps.test.ts — tested notificationTypeIcons/notificationTypeColors exports that a previous, already-merged PR (#1009) intentionally removed as dead code.
• One Dashboard.test.tsx memoization test built entirely around a summary prop that no longer exists now that Dashboard fetches its own vault data internally — its premise no longer matches the component.

Test plan

• pnpm run lint — 0 errors (16 pre-existing warnings remain, non-blocking)
• pnpm run build — succeeds
• pnpm run test — 124/124 files, 1689/1689 tests pass, coverage thresholds met
• CI checks green on this PR (will confirm after push)