feat(reports): unify software search results into single sortable table

[simonjcarr]

Summary

• Replace per-version tables on the Installed Software search view with a single unified table that includes a new Version column — removes the repeated header rows shown in the screenshot issue.
• All columns are sortable (Host, OS, Version, Source, Architecture, Last seen). Default sort is Version desc, matching the prior ordering.
• Version sort reuses the existing compareVersions util (apps/web/lib/version-compare.ts) so semver / RPM epoch / Debian suffix / natural ordering all work correctly (e.g. 3.12.12-3.el10_1.2 sorts above 3.9.25-3.el9_7.2).
• Summary counts (N hosts with this package, N versions) now derive from the displayed rows, so they reflect the active version filter.

No server-action, schema, or export changes — pure UI refactor of apps/web/app/(dashboard)/reports/software/software-report-client.tsx. The CSV/PDF export route is unaffected (it uses a separate query).

Test plan

• pnpm run build passes (verified locally)
• /reports/software → search python3: single table with Version column, default sort Version desc
• Click each column header: asc/desc toggle, chevron icon updates
• Version filters (exact / starts with / between) filter rows correctly and summary counts update
• Empty state renders when no rows match
• CSV and PDF export still work

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