feat: Add theme selector and store user theme preference

[evadecker]

What changed?

Add ability to change themes between system, light, and dark mode, defaulting to system. Resolves #42

Why?

Although the system setting should accommodate most users, it's helpful to be able to toggle between themes for accessibility and for developer testing.

How was this change made?

Added a RadioGroup to the settings page to toggle between themes.

How was this tested?

Manual testing.

Anything else?

Should come back and redesign this settings toggle, but wanted to get it working first.

[changeset-bot]

🦋 Changeset detected

Latest commit: ada137b

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
namesake	Minor

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR

[github-actions]

Coverage Report

Status	Category	Percentage	Covered / Total
🔵	Lines	4.34% ⬆️ +0.13%	122 / 2807
🔵	Statements	4.34% ⬆️ +0.13%	122 / 2807
🔵	Functions	1.36% 🟰 ±0%	1 / 73
🔵	Branches	4.41% 🟰 ±0%	3 / 68

File Coverage

File	Stmts	% Branch	% Funcs	% Lines	Uncovered Lines
Changed Files
convex/constants.ts	100%	100%	100%	100%
convex/schema.ts	100%	100%	100%	100%
convex/users.ts	0%	0%	0%	0%	1-4, 6-7, 9-14, 16-23, 25-32, 34-41, 43-52, 54-58, 60-65, 67-72, 74-79, 81-84
src/components/shared/ListBox.tsx	0%	0%	0%	0%	1, 12-14, 18-27, 30, 33, 35-48, 50-59, 64, 66-84, 86-94, 96-99, 101-102, 108, 114-115, 117-120, 122, 125
src/components/shared/RadioGroup.tsx	0%	0%	0%	0%	1, 8-11, 20-26, 29-31, 33-34, 37, 39-55, 57-63, 66-69, 74
src/routes/settings/index.tsx	0%	0%	0%	0%	1-8, 19, 21-30, 32-35, 37-42, 44-47, 49, 51-55, 57-67, 69-73, 75-80, 82, 84-85, 87-88, 90-93, 95-97, 99-105, 107-114, 116-120, 123-126, 128-130, 132-133, 136-139, 141-142, 145-151, 158-163, 166

Generated in workflow #35