Show password count per folder in the folder list (#79)

[MiMoHo]

Summary

Implements #79: each folder row in the folder list now shows a trailing number indicating how many passwords it directly contains. You approved this part of the request ("I like the suggestion of showing the number of passwords on a folder"); the URIs-per-item part you were unsure about is intentionally not included.

Behavior / design choices

• Direct children only. A folder's number is the count of passwords whose folder == folder.id — i.e. exactly the passwords shown when you open that folder. Subfolders are not recursively summed; each subfolder shows its own count. Happy to switch to recursive totals if you'd prefer.
• Hidden and trashed passwords are excluded, so the number matches the list you see inside the folder.
• Counts come from the full password list, not the search-filtered one, so the numbers stay correct while a search query is active.
• Always shown, including 0 for empty folders (simplest, most predictable). Hiding the 0 is a one-line change if you'd rather.
• Counting is done once per list as a Map<folderId, Int> (groupingBy { }.eachCount()), so it's a single pass regardless of how many folder rows are visible.

Changes

• ItemList.kt: new pure function folderPasswordCounts(passwords); MixedLazyColumn and FolderRow take an optional count and render it as trailingContent (label style, onSurfaceVariant).
• NCPNavHost.kt: at the root and nested folder screens, compute the count map (remembered on the decrypted list) and pass it in.

Testing

• Added JVM unit tests (FolderPasswordCountTest) covering per-folder counts, empty folders/lists, and the hidden/trashed exclusion. ./gradlew testDebugUnitTest is green.
• Manually verified on an Android 15 emulator against a test server: the root folder list shows correct counts (e.g. Private 9, Work 13), subfolders show their own counts, and opening Private lists exactly 9 direct passwords — matching the number.

Note

This contribution was made using AI (Claude). All generated code was proofread and validated by the committer.