fix(a11y): P3 — drop focus:outline-none on inputs; restore global :focus-visible

Phase 10a a11y audit (2026-04-29) flagged seven inputs across the app
that strip the global 2px :focus-visible outline (defined in app.css:251)
without providing a comparable replacement. Net effect: keyboard users
see at most a 1px border-colour shift on focus, sometimes nothing.

The fix removes the focus:outline-none override so the global rule
applies. Affected inputs:

- FilesPage: file-transcript textarea (F2).
- TasksPage: search input, quick-add input, inline list-edit, new-list
  input (T1, T2, T3, plus the new-list rename input).
- HistoryPage: top search, inline title rename, tag-add (H1).
- ImplementationRulesEditor: trigger/surface/task selects + speak-line
  input (S7).
- TaskSidebar, WipTaskList: quick-add inputs (S8).

The 1px focus:border-accent on inputs that had it is retained as a
secondary cue; the global 2px ring is now the primary indicator and
matches button focus across the app.

Resolves: F2, T1, T2, T3, H1, S7, S8.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/lib/pages/HistoryPage.svelte

@@ -581,7 +581,7 @@
       <div class="flex items-center gap-3 px-4 py-2.5">
         <Search size={16} class="text-text-tertiary flex-shrink-0" aria-hidden="true" />
         <input
-          class="flex-1 bg-transparent text-text text-[13px] placeholder:text-text-tertiary focus:outline-none"
+          class="flex-1 bg-transparent text-text text-[13px] placeholder:text-text-tertiary"
           placeholder="Search all transcripts... (try tag:meetings)"
           bind:value={searchQuery}
           data-no-transition
@@ -786,7 +786,7 @@
                     <input
                       type="text"
                       class="w-full bg-bg-input border border-border rounded-lg px-3 py-2 text-[12px]
-                             text-text placeholder:text-text-tertiary focus:outline-none focus:border-accent mb-3"
+                             text-text placeholder:text-text-tertiary focus:border-accent mb-3"
                       placeholder="Name this transcript..."
                       value={item.title || ""}
                       oninput={(e) => { item.title = e.target.value; }}
@@ -828,7 +828,7 @@
                       <input
                         type="text"
                         class="bg-bg-input border border-border rounded-full px-2 py-0.5 text-[10px]
-                               text-text placeholder:text-text-tertiary focus:outline-none focus:border-accent w-[110px]"
+                               text-text placeholder:text-text-tertiary focus:border-accent w-[110px]"
                         placeholder="+ add tag"
                         onkeydown={(e) => handleAddTagKey(e, item)}
                         data-no-transition