test: add regression coverage for proof inspector

[MerlinTheWhiz]

Closes #984

Files created:

• src/features/proof-inspector/utils.ts — Extracted three pure, testable functions from ProofInspectorModal:
  • generateMockProofRecords(emails) — deterministic proof record generation
  • validateProofQuery(query) — query format validation
  • searchProofRecords(records, query) — search/filter logic
• tests/unit/mail/proof-inspector.test.ts — 32 unit tests covering:
  • generateMockProofRecords: deterministic output, folder-based postage status, sender policy mapping, deliveredAt/readAt formatting (13 tests)
  • validateProofQuery: valid G/C addresses, hex hashes (with/without 0x), UUIDs, error on malformed lengths, keyword fallback (11 tests)
  • searchProofRecords: matching by name, email, subject, hash, diagnosticId; case-insensitivity; empty/no-match cases (8 tests)
• tests/e2e/proof-inspector.spec.ts — 7 Playwright tests covering:
  • Modal opens from toolbar, shows correct title/description
  • Quick shortcut buttons displayed
  • Search by sender name shows proof record sections
  • Unmatched query shows "Proof Record Not Found"
  • Format validation for valid/invalid addresses
  • Copy buttons present in results
  • Modal closes on backdrop click

Files modified:

• src/features/proof-inspector/ProofInspectorModal.tsx — Refactored to import from utils.ts instead of inline logic. Zero behavior change.
• tests/unit/mail/provenance.test.ts — Added 10 new tests covering: Stellar key generation, provider resolution (SMTP/Indexer/Federation), isVerified flag for various folders, inspector section structure, deterministic relay node IDs, and rawJson validity.

Verification:

• 46 unit tests pass (32 new + 14 extended)
• Lint passes (npx eslint with 0 warnings)
• tsc --noEmit timed out due to environment resource limits (pre-existing issue)

Local test note:

npm test fails on Node <22 because vite.config.ts imports @cloudflare/vite-plugin, which requires node:module.registerHooks (Node 22+). To run unit tests locally with Node 20, I used an alternate config:

cat > vitest.test.config.ts << 'EOF'
import { defineConfig } from "vitest/config";
import react from "@vitejs/plugin-react";
import tsConfigPaths from "vite-tsconfig-paths";

export default defineConfig({
  plugins: [tsConfigPaths({ projects: ["./tsconfig.json"] }), react()],
  test: {
    include: ["tests/unit/**/*.test.{ts,tsx}"],
  },
});
EOF

npx vitest run --config=vitest.test.config.ts tests/unit/mail/
rm vitest.test.config.ts - I removed it after

Recommended permanent fix: Add a vitest.workspace.ts at the project root that provides a test-only config without the Cloudflare plugin. Or upgrade node to version 22