docs(26-01): complete discovery service plan

- SUMMARY.md: discovery service with cursor pagination
- STATE.md: advanced to plan 2, added decisions, updated progress to 71%
- ROADMAP.md: phase 26 in progress (1/3 plans)
- REQUIREMENTS.md: DISC-02, DISC-03, DISC-04, INFR-02 marked complete

.planning/phases/26-discovery-landing-page/26-01-SUMMARY.md

@@ -0,0 +1,87 @@
+---
+phase: 26-discovery-landing-page
+plan: "01"
+subsystem: server/services
+tags: [discovery, service-layer, cursor-pagination, tdd, drizzle]
+dependency_graph:
+  requires: []
+  provides: [discovery.service.ts]
+  affects: [26-02, 26-03]
+tech_stack:
+  added: []
+  patterns: [cursor-pagination, CursorPage-response-shape, post-query-cursor-filter]
+key_files:
+  created:
+    - src/server/services/discovery.service.ts
+    - tests/services/discovery.service.test.ts
+  modified: []
+decisions:
+  - "Composite cursor for setups: itemCount_id format, filtered post-query in JS for simplicity with grouped SQL"
+  - "createdAt ISO string cursor for recent items: standard timestamp-based pagination"
+  - "No cursor pagination for trending categories: bounded small list (< 50), simple limit is sufficient per RESEARCH.md open question 3"
+  - "Shared CursorPage<T> generic interface for consistent cursor response shape across setups and items"
+metrics:
+  duration: "~2 min"
+  completed_date: "2026-04-10"
+  tasks_completed: 1
+  tasks_total: 1
+  files_created: 2
+  files_modified: 0
+---
+
+# Phase 26 Plan 01: Discovery Service Summary
+
+**One-liner:** Discovery service layer with cursor pagination using Drizzle ORM — getPopularSetups (itemCount_id composite cursor), getRecentGlobalItems (ISO timestamp cursor), getTrendingCategories (simple limit).
+
+## Tasks Completed
+
+| Task | Name | Commit | Files |
+|------|------|--------|-------|
+| 1 (RED) | Discovery service TDD — failing tests | 06b6e93 | tests/services/discovery.service.test.ts |
+| 1 (GREEN) | Discovery service TDD — implementation | d1f8a7a | src/server/services/discovery.service.ts |
+
+## What Was Built
+
+### `src/server/services/discovery.service.ts`
+
+Three exported async functions:
+
+**`getPopularSetups(db, limit=6, cursor?)`**
+- JOINs setups → setupItems (count) → users (displayName)
+- WHERE isPublic=true, GROUP BY setup fields
+- ORDER BY item count DESC, id DESC
+- Cursor: `itemCount_id` composite string, filtered post-query in JS
+- Returns `CursorPage<{ id, name, createdAt, itemCount, creatorName }>`
+
+**`getRecentGlobalItems(db, limit=8, cursor?)`**
+- SELECT * FROM globalItems WHERE createdAt < cursor (if provided)
+- ORDER BY createdAt DESC, LIMIT limit+1 for hasMore detection
+- Cursor: ISO timestamp of last item's createdAt
+- Returns `CursorPage<GlobalItem>`
+
+**`getTrendingCategories(db, limit=12)`**
+- SELECT category, COUNT(id) FROM globalItems WHERE category IS NOT NULL
+- GROUP BY category, ORDER BY count DESC
+- Returns plain `Array<{ name: string; itemCount: number }>` (no cursor)
+
+### `tests/services/discovery.service.test.ts`
+
+11 tests covering:
+- `getPopularSetups`: ordering by count desc, private setup exclusion, hasMore/nextCursor, second page deduplication, creatorName from users.displayName
+- `getRecentGlobalItems`: ordering by createdAt desc, hasMore/nextCursor, second page deduplication
+- `getTrendingCategories`: ordering by count desc, null category exclusion, empty state
+
+## Deviations from Plan
+
+None — plan executed exactly as written.
+
+The test used a dynamic import pattern for `eq` which was corrected to a static import (minor code quality fix before RED commit).
+
+## Verification
+
+- `bun test tests/services/discovery.service.test.ts`: 11 pass, 0 fail
+- `bun test` full suite: 290 tests — same pass/fail ratio as before (15 pre-existing failures from `withImageUrl` storage service export issue, unrelated to this plan)
+
+## Self-Check
+
+Checked below.