Add configurable lift angles and beat-rate calculations

[AngryBrit]

Summary

• add configurable lift-angle management with a dedicated settings screen and localization updates
• update timegrapher calculations and UI flows to use configured lift angles across flip detail views
• include related frontend/template updates plus npm metadata needed for the new UI behavior

Test plan

• Open Settings and verify lift-angle management can add/edit values
• Open a flip detail page and confirm timegrapher metrics use selected lift angle
• Validate language strings render correctly in supported locales
• Run app smoke test (py .\\app.py) and check affected pages load without errors

Review note

• manufacturer-name normalization was split into a focused stacked PR for easier review: Normalize manufacturer variants in lift-angle lookup AngryBrit/mainplate#1

Made with Cursor

[AngryBrit]

Addressed Bugbot findings in a follow-up commit:\n\n- preserve custom lift-angle overrides during WatchGuy cache refresh (ON CONFLICT ... DO UPDATE ... WHERE source != 'custom')\n- normalize manufacturer search input consistently in /api/lift-angles/search\n- align SQL-side manufacturer canonicalization with separator/whitespace normalization used by the API\n\nPushed to eat/lift-angles in commit 8f2403c.