Standardize monorepo pipeline: test, lint, typecheck across all workspaces

Previously only 2-3 workspaces participated in each turbo task. This
expands test, lint, and typecheck to cover all 11 workspaces with
parallel execution and caching.

Test pipeline:
- Move from single root vitest to per-workspace test scripts via turbo
- Shared vitest config (vitest.shared.ts) with passWithNoTests
- Per-workspace configs re-export the shared base
- Mobile uses Jest (jest-expo + React Native Testing Library)
- Add node-environment GPX tests verifying linkedom fallback
- Add i18n mobile init tests
- Exclude apps/mobile from root vitest (uses Jest separately)

Lint pipeline:
- Add eslint lint script to all 9 previously unlinted workspaces
- Standardize all scripts to "eslint ." with shared root config
- Add .expo/ to global ESLint ignores
- Fix lint errors: unused imports in api/types, export parseGpx

Typecheck pipeline:
- Add "typecheck": "tsc" to all 8 packages
- Add @types/node (catalog) to gpx and db packages
- Fix mobile app.config.ts: remove deprecated experiments.monorepo
  and newArchEnabled (both default in Expo SDK 55)
- Add allowImportingTsExtensions to mobile tsconfig

Shared package compatibility (mobile-app Phase 1.3):
- Add linkedom as explicit dependency to @trails-cool/gpx
- Add initI18nMobile() export to @trails-cool/i18n
- Confirm @trails-cool/types is pure interfaces (no DOM deps)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

packages/gpx/src/parse.ts

@@ -15,7 +15,7 @@ async function getDOMParser(): Promise<typeof DOMParser> {
   return _LinkedDOMParser;
 }
 
-function parseGpx(xml: string): GpxData {
+export function parseGpx(xml: string): GpxData {
   // Synchronous path for browser
   if (typeof DOMParser !== "undefined") {
     return parseGpxWithParser(new DOMParser(), xml);
@@ -26,7 +26,7 @@ function parseGpx(xml: string): GpxData {
     const { DOMParser: LP } = require("linkedom");
     return parseGpxWithParser(new LP() as unknown as DOMParser, xml);
   } catch {
-    throw new Error("DOMParser not available — install linkedom for Node.js");
+    throw new Error("DOMParser not available — install linkedom");
   }
 }