Add Wikipedia watch and PDA backfill categories

[Seungpyo1007]

Summary

• Add verified Wikipedia cross-reference pages for watch and PDA categories, with the category-aware matching gates used for tablets.
• Add the needed brand tokens and tests for page routing, exact headings, dry runs, and category-specific cache paths.
• Keep dry-run HTML caching off so reading TechAPI does not create HTML files there. The dry runs used JSONL caches under the local Temp directory.

The English Wikipedia API reported Xiaomi_Mi_Watch missing and Palm_T|X invalid, so those two stash entries were omitted. Redirecting titles were retained.

TechAPI dry runs

Category	Checked	Confirm	Ambiguous	Not found	Contradict
Watch	300	0	11	286	3
PDA	125	0	4	116	5

Both runs used --data-root C:/Users/29/Desktop/TechAPI --dry-run with no apply flag. No TechAPI data files were written.

Validation

• python -m pytest -q --basetemp C:/Users/29/AppData/Local/Temp/techengine-pytest-watch-pda-full
• python -m mypy app
• python -m ruff check app tests
• python -m ruff format --check app/verify/wikipedia_smartphone_backfill.py tests/verify/test_wikipedia_smartphone_backfill.py
• git diff --check