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

[ilmoniemi]

User Story

As a Pyrycode mobile user, I want to open Settings → "Archived discussions", see the discussions my 30-day auto-archive has evicted, and restore any I want back, so an auto-archive doesn't lose work I still care about.

Context

Plan Phase 3 specifies an "Archived discussions" view reachable from Settings. The repository primitives are in place: archive(conversationId) from #3, retain-on-archive semantics + the archived-conversations observable + the seeded archived discussion from #93, and unarchive(conversationId) from #96. This ticket builds the screen, its ViewModel, and the Settings row that navigates to it.

The 30-day auto-archive mechanism itself is a separate ticket; this slice assumes archived state is reachable (which the seed in #93 guarantees for manual verification).

Acceptance Criteria

• Settings screen gains a row "Archived discussions" that navigates to a new screen (route added to the navigation graph)
• Screen displays a LazyColumn of conversations matching isPromoted = false AND archived = true, observed from the repository
• Each row renders: discussion name (or its auto-generated label), last-message preview, archive date
• Long-press on a row reveals a "Restore" affordance; selecting it invokes unarchive(conversationId) via the ViewModel and the row leaves the list
• Returning to the main Channel List shows the restored discussion in the Recent discussions section
• Empty state renders the copy "No archived discussions"
• TopAppBar shows a back arrow and the title "Archived discussions"
• ViewModel unit test covers the archived-list observation and the restore-action path

Technical Notes

• The screen is stateless; hoist state to a new ViewModel exposing a sealed UiState + Event per the MVI convention in CLAUDE.md.
• Restore affordance: long-press is the spec; if the architect determines swipe-to-restore would be more consistent with the rest of the app, they may substitute — but exactly one gesture, not both.

Size Estimate

S

Figma

N/A — no dedicated Archived Discussions view exists in the canonical Figma file (g2HIq2UyPhslEoHRokQmHG) yet. The screen should derive its visuals from the existing Recent Discussions row treatment built in #69 (Channel List, node 15-8), with a reduced-contrast / muted treatment to signal the archived state. A dedicated Figma view for this screen is recommended as a follow-up — the architect should flag this back via needs-rework:po if a derived spec is judged insufficient, so Juhana can add the view before development starts.

Blocked by

• feat(data): retain conversations on archive() + expose archived filter + seed #93 — retain-on-archive semantics, archived-conversations observable, seeded archived discussion in the Fake.
• feat(data): add unarchive() primitive to ConversationRepository + Fake impl #96 — unarchive(conversationId) primitive on ConversationRepository.

Both are now CLOSED; the GitHub blocked-by links resolve mechanically via the dispatcher.

Split from

#77

[ilmoniemi]

Re-pointed to also depend on #96 as part of #93's split. The unarchive() primitive that this screen's restore action invokes now lives in #96 (the foundation slice in #93 only changes archive semantics + exposes archived observability + seeds; the inverse primitive ships separately). Both must close before this ticket is unblocked — dispatcher will handle that mechanically.

[ilmoniemi]

Refinement (rework): updated stale references — the "data slice split from #77" is now the pair #93 (foundation: retain-on-archive + archived observable + seed) and #96 (unarchive primitive). Body's Context and Blocked-by sections now name them explicitly. Both blockers are CLOSED, so dispatcher will unblock this mechanically. Size remains S; AC, Technical Notes, and Figma justification are all unchanged.

[ilmoniemi]

🤖 Product Owner — creates structured issues

po agent has completed work on this ticket.

Agent output (click to expand)

Rework complete. Updated the stale "data slice split from #77" prose to explicitly name #93 (foundation) and #96 (unarchive primitive) in both Context and Blocked-by sections. Both blockers are now CLOSED, so dispatcher will unblock mechanically. Size remains S; AC and Figma justification unchanged.

Ready for human review. Move to the next column when approved.