fix: make search bar always visible instead of toggle-behind-icon

Removed the magnifying-glass toolbar button and the isSearching state
it drove -- .searchable() now shows the search field unconditionally,
which is simpler and was requested after hands-on use showed the extra
tap added no value. Updated the spec to match.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01WYqycDFsynHH9VnnK7LNSf

docs/superpowers/specs/2026-05-21-mypass-design.md

@@ -152,7 +152,7 @@ NavigationSplitView(columnVisibility:)
 `NavigationSplitView` is used on **both** platforms instead of maintaining separate iOS/macOS navigation code. On iPhone-width layouts it automatically collapses the sidebar into an overlay; on iPad/Mac it can sit persistently alongside the detail column. This behavior is built into the component — no platform-specific branching needed for it.
 
 - **Hamburger button** (leading toolbar item, `"line.3.horizontal"`) toggles `columnVisibility` between `.all` and `.detailOnly`, showing/hiding the sidebar.
-- **Search icon** (trailing toolbar item, `"magnifyingglass"`) toggles a `.searchable()` bar over `EntryListView`; tapping again hides it and clears the query.
+- **Search** is always visible via `.searchable()` over `EntryListView` (no toggle icon -- changed 2026-09-19 after hands-on use showed the extra tap added no value over an always-present search field).
 - Swipe-to-delete on entry rows; toolbar `+` button opens `EntryEditView` for a new entry (see "Add-entry flow" below).
 - Tapping a password field in `EntryDetailView` copies to clipboard (clears after 30 s).
 - TOTP code displays with a countdown ring and refreshes automatically.