chore: clear the mechanical lint and type findings

Dead imports and locals removed, each blocks keyed, `any` narrowed to unknown.
Two context setters kept their calls and lost only the unused binding; the
settings redirect no longer awaits a parent whose data it discards. A leading
underscore now marks a binding that only holds a position.

frontend/src/lib/components/forms/login-form.svelte

@@ -21,7 +21,7 @@
 					<Field.Field>
 						<Field.Label for="email">Email</Field.Label>
 						<Input {...login.fields.email.as('email')} />
-						{#each login.fields.email.issues() ?? [] as issue}
+						{#each login.fields.email.issues() ?? [] as issue, i (i)}
 							<Field.Error>{issue.message}</Field.Error>
 						{/each}
 					</Field.Field>
@@ -30,7 +30,7 @@
 					<Field.Field>
 						<Field.Label for="password">Password</Field.Label>
 						<Input {...login.fields.password.as('password')} />
-						{#each login.fields.password.issues() ?? [] as issue}
+						{#each login.fields.password.issues() ?? [] as issue, i (i)}
 							<Field.Error>{issue.message}</Field.Error>
 						{/each}
 					</Field.Field>