test: add bundled TypeScript import helper

[JustYannicc]

Summary

• Replace the dependency-free-only scripts/lib/ts-import.mjs transform with an esbuild bundle-backed TS/TSX import helper.
• Add safe default stubs for Electron, React/JSX, common renderer globals, and static assets so selected production modules can be imported in Node tests.
• Convert the shallow browser-search history export grep into an executable import test that loads src/main/browser-search-history.ts and exercises resolveInput() through its relative resolver dependency.

Baseline

scripts/test-browser-search-lag-fix.mjs previously read source text and grepped for browser-search history names. That proved text existed, but it could not prove the module loaded, that relative imports resolved, or that exported behavior still worked.

Validation

• Codex LSP diagnostics: no errors for scripts/lib/ts-import.mjs and scripts/test-browser-search-lag-fix.mjs.
• node --test scripts/test-browser-search-lag-fix.mjs: 11 pass, 0 fail.
• TSX smoke check: importTs(src/renderer/src/icons/Calendar.tsx) returned a default function.
• npm test: 25 pass, 0 fail, 1 skipped (Renderer crash recovery (live Electron) skipped because Electron is not launchable here).

Risks

• The helper intentionally stubs host APIs; tests that need real Electron or browser behavior should still use dedicated live harnesses.
• Default stubs are broad enough for import-time tests, but module-specific behavior tests may need custom stubs via importTs(..., { stubs }).

[JustYannicc]

Superseded by #532 (fix(validation): restore project checks), which consolidates this validation/build change with the related source PRs. Closing this PR in favor of the upstream replacement.