# Project Retrospective

*A living document updated after each milestone. Lessons feed forward into future planning.*

## Milestone: v1.0 — MVP

**Shipped:** 2026-06-10
**Phases:** 6 | **Plans:** 42 | **Sessions:** not tracked

### What Was Built
- Unified color-coded Fastmail calendar (shared + personal) with full event CRUD written back via CalDAV — read views, recurrence/DST expansion, all-day, and an enqueue-only outbox write path.
- Installable React PWA behind Authelia OIDC, taken live over Pangolin/Newt and verified end-to-end on desktop and iOS.
- Shared collaborative lists with real-time SSE co-edit sync, and VAPID Web Push for reminders / event-change / list alerts.

### What Worked
- **Dev-auth bypass to build behind a deferred gate (D-14):** Phases 2–3 were built against a documented bypass while live Authelia/Pangolin infra wasn't ready, with no rework when Gate 2 finally ran live in Phase 3.
- **Wave-based parallel plans** within phases kept large phases (Phase 3 = 12 plans) moving.
- **Enqueue-only outbox with optimistic 202** cleanly separated request handling from the slow CalDAV write, and made create-before-delete ordering + etag/412 handling tractable.

### What Was Inefficient
- **A long tail of bugs only reproduced under live conditions** (Newt MTU blackhole, OIDC state-cookie race, write-path timezone/identity/join/cache bugs, all-day off-by-one, color collisions, silent Android notifications, session-cookie expiry). Building behind the bypass too long delayed their discovery — they all surfaced at once during live bring-up.
- **Background workers silently failed:** node-cron 4.2.1 skipped *every* scheduled tick in the long-lived API process, so reminders/poller/outbox never fired on schedule — caught late, during Phase 5 UAT, not by tests.
- **Repeated mobile-only defects could only be found by the operator on real devices** because the test harness is desktop-Chromium and the prod PWA is behind OIDC (→ backlog 999.12).

### Patterns Established
- **`setInterval`, not node-cron, for in-process schedulers** (node-cron silently no-ops in a long-lived process). Do not reintroduce node-cron.
- **drizzle-kit `generate`+`migrate`, never `push`, on MariaDB** — `push` emits a false destructive (truncate) diff against populated MariaDB.
- **iOS-Safari standalone behavior is a human/device checkpoint**, not a playwright-cli check — keep those as explicit manual gates.
- **Run `tsc --noEmit` (both apps) in the post-merge gate** — esbuild strips types so vitest stays green while tsc fails.

### Key Lessons
1. Bring the real external topology (auth + tunnel) up *early* and behind a small reversible config, rather than deferring all live verification — the live-only bug class is large and clusters at first contact.
2. Long-running Node schedulers need an integration-level "does it actually fire on a tick" check; unit tests pass while the scheduler silently does nothing.
3. Push has hard platform footguns (iOS revokes after 3 silent pushes; standalone install mandatory; VAPID key truncation = silent Apple 403) — encode them as guards from day one, not after a missed notification.

### Cost Observations
- Model mix: not tracked
- Sessions: not tracked
- Notable: TDD red→green discipline is visible in commit history, but per-commit `gate_status:` trailers were never emitted across the milestone — the ship-time TDD audit had nothing structured to aggregate. Wire gate_status trailers in v1.x if the audit is wanted.

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## Cross-Milestone Trends

### Process Evolution

| Milestone | Sessions | Phases | Key Change |
|-----------|----------|--------|------------|
| v1.0 | n/a | 6 | Established GSD plan→execute→verify→ship→complete loop; dev-auth bypass for gated infra; milestone-branch + Gitea PR shipping |

### Cumulative Quality

| Milestone | Tests | Coverage | Zero-Dep Additions |
|-----------|-------|----------|-------------------|
| v1.0 | PWA 191 + API broker/events 114 green | not measured | n/a |

### Top Lessons (Verified Across Milestones)

1. (pending second milestone to cross-validate)