style: Phase 1+2 — FA→Lucide, variant-* → preset-*, dark mode forms

Phase 1 (global quick wins):
- app.css: add global dark mode utility for .input/.select/.textarea
- events menu nav + layout: replace all FontAwesome icons with Lucide
- events settings: replace FA icons, standardize variant-* → preset-*

Phase 2 (module-by-module migration):
- root +layout.svelte: fix hardcoded banner colors → preset-filled-error/warning
- journals entry list: replace slate-* with gray-*, HSL eye colors → CSS tokens
- pres mgmt presenter view: variant-soft-warning → preset-tonal-warning, FA edit → Lucide
- badges (4 files): variant-* → preset-*, FA spinner → Lucide Loader2, dynamic alert fix
- events session list + event hub: variant-soft/filled → preset-tonal/filled
- leads module (12 files): complete variant-* → preset-* migration across all
  exhibitor sign-in, QR scanner, manual search, tracking list, manage tab,
  custom questions, license list, exhibit page, lead detail page + form

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/routes/journals/ae_comp__journal_entry_obj_li.svelte

@@ -602,8 +602,8 @@ Journal ID: ${journals_journal_entry_obj?.journal_id}
                                     .hide_professional)}
                         class="journal__content
                     w-full p-1
-                    bg-slate-100 text-gray-900
-                    dark:bg-slate-900 dark:text-gray-100
+                    bg-gray-100 text-gray-900
+                    dark:bg-gray-900 dark:text-gray-100
                     shadow-lg rounded-lg
                     border border-gray-200 dark:border-gray-700
                     text-wrap text-sm font-mono whitespace-pre-wrap
@@ -730,15 +730,13 @@ Journal ID: ${journals_journal_entry_obj?.journal_id}
                         {#if journals_journal_entry_obj.hide}
                             <EyeOff
                                 strokeWidth="1"
-                                color="hsla( 0, 100%, 50%, .5)"
-                                class="inline-block"
+                                class="inline-block text-error-500/60"
                             />
                             <span class="hidden md:inline">Hidden</span>
                         {:else}
                             <Eye
                                 strokeWidth="2.5"
-                                color="hsla( 120, 100%, 25%, .5)"
-                                class="inline-block"
+                                class="inline-block text-success-700 dark:text-success-400"
                             />
                             <span class="hidden lg:inline">Visible</span>
                         {/if}