feat: sync heartbeats, eval:trend --team, setup guide, 10 new tests

- 005_sync_heartbeats.sql migration for connectivity testing
- eval:trend --team flag pulls team eval data (graceful fallback)
- docs/TEAM_SYNC_SETUP.md step-by-step setup guide
- Design doc status updated to Phase 2 complete
- 10 new tests for sync show formatting functions

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

docs/TEAM_SYNC_SETUP.md

@@ -0,0 +1,132 @@
+# Team Sync Setup Guide
+
+Team sync lets your team share eval results, retro snapshots, QA reports, ship logs, and Greptile triage data via a shared Supabase store. All sync is optional and non-fatal — without it, everything works locally as before.
+
+## Prerequisites
+
+- A [Supabase](https://supabase.com) project (free tier works)
+- gstack v0.3.10+
+
+## Step 1: Create a Supabase project
+
+1. Go to [supabase.com](https://supabase.com) and create a new project
+2. Note your **Project URL** (e.g., `https://xxxx.supabase.co`)
+3. Note your **anon/public key** from Settings > API
+
+## Step 2: Run migrations
+
+In the Supabase SQL Editor, run these files **in order**:
+
+```
+supabase/migrations/001_teams.sql
+supabase/migrations/002_eval_runs.sql
+supabase/migrations/003_data_tables.sql
+supabase/migrations/004_eval_costs.sql
+supabase/migrations/005_sync_heartbeats.sql
+```
+
+Copy-paste each file's contents into the SQL editor and run.
+
+## Step 3: Create your team
+
+In the SQL editor, create a team and add yourself:
+
+```sql
+-- Create team
+INSERT INTO teams (name, slug) VALUES ('Your Team', 'your-team-slug');
+
+-- After authenticating (Step 5), add yourself as owner:
+-- INSERT INTO team_members (team_id, user_id, role)
+-- VALUES ('<team-id>', '<your-user-id>', 'owner');
+```
+
+Note the team slug — you'll need it in the next step.
+
+## Step 4: Configure your project
+
+Copy the example config to your project root:
+
+```bash
+cp .gstack-sync.json.example .gstack-sync.json
+```
+
+Edit `.gstack-sync.json` with your Supabase details:
+
+```json
+{
+  "supabase_url": "https://YOUR_PROJECT.supabase.co",
+  "supabase_anon_key": "eyJ...",
+  "team_slug": "your-team-slug"
+}
+```
+
+**Important:** Add `.gstack-sync.json` to `.gitignore` if it contains sensitive keys, or commit it if your team uses the same Supabase project (the anon key is safe to commit — RLS protects the data).
+
+## Step 5: Authenticate
+
+```bash
+gstack-sync setup
+```
+
+This opens your browser for Supabase OAuth. After authenticating, tokens are saved to `~/.gstack/auth.json` (mode 0600).
+
+**For CI/automation:** Set the `GSTACK_SUPABASE_ACCESS_TOKEN` env var instead of running setup.
+
+## Step 6: Verify
+
+```bash
+gstack-sync test
+```
+
+Expected output:
+```
+gstack sync test
+────────────────────────────────────
+  1. Config:        ok (team: your-team-slug)
+  2. Auth:          ok (you@email.com)
+  3. Push:          ok (123ms)
+  4. Pull:          ok (1 heartbeats, 95ms)
+────────────────────────────────────
+  Sync test passed ✓
+```
+
+## Step 7: See your data
+
+```bash
+gstack-sync show              # team summary dashboard
+gstack-sync show evals        # recent eval runs
+gstack-sync show ships        # recent ship logs
+gstack-sync show retros       # recent retro snapshots
+gstack-sync status            # sync health check
+bun run eval:trend --team     # team-wide test trends
+```
+
+## How it works
+
+When sync is configured, skills automatically push data after completing their primary task:
+
+- `/ship` pushes a ship log after PR creation (Step 8.5)
+- `/retro` pushes the snapshot after saving to `.context/retros/` (Step 13)
+- `/qa` pushes a report after computing the health score (Phase 6)
+- `/review` pushes Greptile triage entries after history file writes
+- Eval runs are pushed automatically by `EvalCollector.finalize()`
+
+All pushes are non-fatal. If sync fails, entries are queued in `~/.gstack/sync-queue.json` and retried on the next push or via `gstack-sync drain`.
+
+## Troubleshooting
+
+| Problem | Fix |
+|---|---|
+| "No .gstack-sync.json found" | Copy `.gstack-sync.json.example` and fill in your values |
+| "Not authenticated" | Run `gstack-sync setup` |
+| Push fails with 404 | Run the migration SQL files in order |
+| "Connection failed" | Check your Supabase URL and that the project is running |
+| Queue growing | Run `gstack-sync drain` to flush |
+
+## Adding team members
+
+Each team member needs to:
+
+1. Have `.gstack-sync.json` in their project (commit it or share it)
+2. Run `gstack-sync setup` to authenticate
+3. Be added to `team_members` in Supabase (by an admin)

docs/designs/TEAM_COORDINATION_STORE.md

@@ -1,7 +1,7 @@
 # Team Coordination Store: gstack as Engineering Intelligence Platform
 
 > Design doc for the Supabase-backed team data store and universal eval infrastructure.
-> Authored 2026-03-15. Status: approved, not yet implemented.
+> Authored 2026-03-15. Status: Phase 1 complete. Phase 2 complete (skill hooks, sync test/show, team trends). Phase 3-4 not started.
 
 ## Table of Contents