feat(ui): Archived Discussions screen + ViewModel + Settings entry (#94)

[ilmoniemi]

What

• New ArchivedDiscussionsScreen + ArchivedDiscussionsViewModel under ui/settings/. MVI shape per CLAUDE.md: sealed UiState (Loading | Empty | Loaded | Error) and sealed Event (RestoreRequested | BackTapped).
• Settings → Storage row "Archived discussions" navigates to the new screen (replaces the previous placeholder "Archived conversations / 11 archived" row).
• New nav route Routes.ARCHIVED_DISCUSSIONS wired in MainActivity.PyryNavHost.
• Koin: one viewModel { ArchivedDiscussionsViewModel(get()) } line in AppModule.
• Strings: archived_discussions_title, archived_discussions_empty, archived_discussions_settings_row, restore_action. Reused cd_back.

VM consumes repository.observeConversations(ConversationFilter.Archived) and applies a !isPromoted post-filter (so archived channels are excluded; only archived discussions show). RestoreRequested(id) fires viewModelScope.launch { repository.unarchive(id) } — the row drops naturally from the next upstream emission.

Screen reuses the existing ConversationRow with Modifier.alpha(0.65f) for the muted/archived treatment (mirrors the discussion-row treatment in DiscussionListScreen). Long-press → DropdownMenu with one "Restore" item — exactly one gesture per ticket guidance.

Issue

Closes #94

Blocked-by #93 and #96 are both merged; the archived stream and unarchive primitive are live.

Testing

• ./gradlew test — passes. New ArchivedDiscussionsViewModelTest covers: initial Loading, Archived filter is requested, post-filter drops promoted-archived, Empty (empty list + only-channels), RestoreRequested calls unarchive with the right id, BackTapped is a no-op for the repo, stream-error → Error, null/blank exception message → non-blank fallback.
• ./gradlew lint — clean.
• ./gradlew assembleDebug — succeeds.
• ./gradlew connectedAndroidTest — not run (no device/emulator in this dev env).

Architecture compliance

• Stateless screen, state hoisted to the VM; state: UiState, onEvent: (Event) -> Unit shape.
• VM exposure: StateFlow<UiState> via .stateIn(viewModelScope, SharingStarted.WhileSubscribed(5_000L), Loading) — mirrors DiscussionListViewModel.
• No swipe gesture (spec: exactly one gesture). Long-press dropdown matches DiscussionListScreen's convention.
• BackTapped is Unit in the VM; back navigation handled by NavHost (matches DiscussionListEvent.BackTapped).
• No optimistic state on restore: repository's MutableStateFlow.update re-emits and the filter drops the row.

Open items (per spec, deferred)

• archivedAt timestamp field on Conversation is a follow-up (separate ticket when the 30-day auto-archive worker lands). For now the trailing slot renders formatRelativeTime(lastUsedAt), which for the seeded archived discussion prints "Apr 15, 2026" — acceptable as the "archive date" surface for this slice.
• Settings row no longer shows a live count of archived items (the previous "11 archived" was placeholder copy). Adding a real count expands scope into another SettingsViewModel StateFlow and is deferred per the spec.

Note on spotless

./gradlew spotlessCheck reports one pre-existing violation in app/src/main/java/de/pyryco/mobile/ui/settings/ThemePickerDialog.kt:48 (chained-call line-break) that exists on main and is not in this diff. Per scope discipline (CLAUDE.md "Bug Found Out of Scope") I left it alone — happy to file as a separate cleanup ticket on request.

🤖 Generated with Claude Code

[ilmoniemi]

Code Review: #94

Decision: FAIL

Findings

• [MUST FIX] app/src/androidTest/java/de/pyryco/mobile/ui/settings/SettingsScreenTest.kt:25,44 — SettingsScreen(...) is invoked without the new required onOpenArchivedDiscussions parameter. ./gradlew :app:compileDebugAndroidTestKotlin fails with:

  e: SettingsScreenTest.kt:29:21 No value passed for parameter 'onOpenArchivedDiscussions'.
  e: SettingsScreenTest.kt:48:21 No value passed for parameter 'onOpenArchivedDiscussions'.
  

  The PR's "Testing" section notes connectedAndroidTest was skipped, which is why this slipped through — but the instrumented test sources also won't compile, so any future connectedAndroidTest run on this branch will fail before it boots an emulator. Fix: add onOpenArchivedDiscussions = {} to both call sites (matches the preview-level treatment in SettingsScreen.kt:297,311). A grep / codegraph_callers SettingsScreen against the pre-change shape would have caught this — please run that check on any future signature change.

Other observations (none blocking)

• VM, screen, navigation wiring, Koin entry, strings, and tests all match the spec verbatim — package layout, WhileSubscribed(5_000L), !isPromoted post-filter, BackTapped → Unit in VM with NavHost interception, Modifier.alpha(0.65f) muted treatment, long-press DropdownMenu (one gesture, not both).
• Unit tests are thorough: filter capture, post-filter for archived-channels, both Empty paths, RestoreRequested → unarchive(id), BackTapped no-op, stream error, null/blank exception message fallback. Covers the AC's "ViewModel unit test covers the archived-list observation and the restore-action path."
• ./gradlew test, ./gradlew lint, ./gradlew assembleDebug are clean. The pre-existing spotlessCheck violation in ThemePickerDialog.kt:48 is on main, not in this diff — agreed it's out of scope for this ticket.
• M3 token usage clean; no hardcoded colors, typography, or shapes. The alpha(0.65f) constant mirrors DiscussionListScreen's established pattern.

Summary

One blast-radius miss: the new required onOpenArchivedDiscussions parameter on SettingsScreen wasn't propagated to SettingsScreenTest.kt, breaking compileDebugAndroidTestKotlin. Everything else in the PR is solid and faithful to the spec. Add the two onOpenArchivedDiscussions = {} arguments to the test file and re-run ./gradlew :app:compileDebugAndroidTestKotlin to confirm before re-review.

[ilmoniemi]

Code Review: #94

Decision: PASS

Findings

• [NIT] ArchivedDiscussionsScreen.kt:97 — ConversationRow(onClick = {}) still produces a ripple on tap even though tap is a no-op. Same precedent in DiscussionListScreen.kt:200 (onClick = onTap is the live nav, not a no-op), so this is a deviation only here. Not blocking; if you want, swap to a non-clickable variant in a future cleanup. Long-press-as-sole-action is consistent with the spec and the existing pattern, so leaving it as-is is fine for this slice.
• [NIT] ArchivedDiscussionsScreen.kt:60,68 — "Loading…" and "Couldn't load archived discussions: ${state.message}" are hard-coded strings rather than stringResource. Same pattern is in DiscussionListScreen.kt:89,97, so this is codebase-consistent — flagging only because a future strings-pass should sweep both.
• [NIT] The "last-message preview" AC item maps to an empty supporting-text slot (lastMessage = null). Documented in the spec's open questions as a Phase 1 deferral; acceptable.

Summary

Implementation matches the spec verbatim: VM uses observeConversations(ConversationFilter.Archived) + !isPromoted post-filter, .catch → Error(message) with non-blank fallback, .stateIn(WhileSubscribed(5_000L), Loading). Restore is a fire-and-forget viewModelScope.launch { repository.unarchive(id) }. Screen mirrors DiscussionListScreen shape (Scaffold + TopAppBar + back arrow + LazyColumn + long-press DropdownMenu + alpha(0.65f) muted row). Settings row updated in place; nav graph extends with Routes.ARCHIVED_DISCUSSIONS; Koin wiring is one line. Strings extracted to strings.xml. SettingsScreenTest propagates the new callback.

VM tests cover all the spec's required scenarios (Loading initial, Archived filter passed, archived-channels dropped, empty source, all-channels-empty, restore-id captured, back-doesn't-dispatch, error path with raw message, non-blank fallback). Three @Preview variants (Loaded/Empty/Long-press menu) provided.

./gradlew :app:testDebugUnitTest and :app:lintDebug both green. Manual verification of the seeded archived discussion + dark mode is the developer's responsibility (per spec § Manual verification).