Use localized pluralization for sidebar heading counts

[productengineered]

Source

CodeRabbit finding #9 from PR #2.

What

The markdown sidebar footer uses a ternary for pluralization:
`total == 1 ? "heading" : "headings"`

This doesn't support languages with complex plural rules (e.g., Russian has 3 plural forms, Arabic has 6).

Why deferred

The existing JSONL sidebar uses the exact same ternary pattern for "line"/"lines". Fixing one without the other would be inconsistent. This should be addressed as a single pass across all sidebar footers when localization becomes a priority.

When to revisit

When adding localization support to the app (String Catalogs / stringsdict).

Files

• app/Parsely/Parsely/Views/Screens/MarkdownSidebarView.swift (lines 125-127)
• app/Parsely/Parsely/Views/Screens/SidebarView.swift (lines 117-123) — same pattern

[productengineered]

Additional finding from CodeRabbit review round 2:

The "No headings match" text in MarkdownSidebarView.swift (line 65) uses string interpolation instead of String(localized:) with a format placeholder. Same localization pattern as the footer counts — should be addressed together in the i18n pass.