2FA

/puter/src/i18n/translations/ru.js
  180:34  error  Irregular whitespace not allowed    no-irregular-whitespace
  257:9   error  Duplicate key 'storage_puter_used'  no-dupe-keys

/puter/src/UI/Settings/UITabSecurity.js
  13:13  error  'user' is not defined        no-undef
  31:13  error  'user' is not defined        no-undef
  32:70  error  'user' is not defined        no-undef
  36:30  error  'user' is not defined        no-undef
  40:82  error  'user' is not defined        no-undef
  41:83  error  'user' is not defined        no-undef
  87:41  error  'api_origin' is not defined  no-undef

/puter/src/UI/UIWindow2FASetup.js
  39:33  error  'api_origin' is not defined  no-undef
  51:37  error  'api_origin' is not defined  no-undef
  69:37  error  'api_origin' is not defined  no-undef

/puter/src/UI/UIWindowLogin.js
  202:73  error  'api_origin' is not defined  no-undef
  271:73  error  'api_origin' is not defined  no-undef

This also fixes the "Reset Colors" button not adjusting the sliders.

Also, we can ask the CustomElementRegistry if it has an entry with a
given name, instead of polluting the window object.

Convert UIWindowThemeDialog to components

These two seem like bugs but are unclear to me how to fix, so I've added
FIXMEs.

/puter/packages/backend/src/routers/kvstore/clearItems.js
  41:32  error  'DB_MODE_WRITE' is not defined  no-undef

/puter/packages/backend/src/routers/whoami.js
  104:35  error  'db' is not defined  no-undef

Run the ESLint static analysis tool on any code that is submitted, to
find possible bugs such as undefined functions and variables. We may
want to adjust the ESLint settings over time, but this seems like a
good start.

This is merged into the previous check-translations.yml action, because
that's also a form of linting. Possibly that could be reimplemented as
an ESLint plugin.

No `.qr-code-checkbox input`s now exist. Also, `.code-confirm-btn` is
only used by CodeEntryView, which doesn't use this Button component.

This needs a better solution for configuring the button's CSS classes,
but this works for now.

We have 7 of these, which all have very similar code. Let's deduplicate
them! :^)

This previously had code for the cancel button, but that cancel button
didn't exist. I've left the previous on-cancel code commented out with
a TODO.

I noticed during this that emptying the trash from inside the Trash
window uses a different code path without a progress dialog, so I've
added a TODO to merge that in. I tried just using it directly but the
behaviour is a bit different. (The Trash one makes all the items fade
out.)

Previously we showed "Moving /foo" which was confusing.

Also, make use of i18n replacements instead of gluing strings together,
because other languages might put the words in a different order. For
now, I've modified all the translations so that the "Moving foo" text
will appear as it did before, but these will require someone who
actually knows the different languages to check and correct them.

Using npm install appears to have different results depending on whether
or not the parent directory of the puter repository happens to have a
package.json file (ex: nested workspaces).