add privacy-first analytics with progressive event collection

Three-layer pipeline: Plug for all HTTP requests (no JS needed), LiveView
hook for SPA navigations, JS hook for screen width. ETS-backed buffer
batches writes to SQLite every 10s. Daily-rotating salt for visitor hashing.
Includes admin dashboard with date ranges, visitor trends, top pages,
sources, devices, and e-commerce conversion funnel. Oban cron for 12-month
data retention.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

PROGRESS.md

@@ -9,7 +9,7 @@
 - Image optimization pipeline (AVIF/WebP/JPEG responsive variants)
 - Shop pages (home, collections, products, cart, about, contact, error, delivery, privacy, terms)
 - Mobile-first design with bottom navigation
-- 898 tests passing, 100% PageSpeed score
+- 972 tests passing, 100% PageSpeed score
 - SQLite production tuning (IMMEDIATE transactions, mmap, WAL journal limit)
 - Variant selector with color swatches and size buttons
 - Session-based cart with real variant data (add/remove/quantity, cross-tab sync)
@@ -61,7 +61,7 @@ Plans: [admin-redesign.md](docs/plans/admin-redesign.md) | [admin-font-loading.m
 | ~~29~~ | ~~Printful webhooks~~ | 25 | 1.5h | done |
 | | **Next up** | | | |
 | ~~30~~ | ~~Admin UI tweaks for Printful~~ | 25 | 30m | done |
-| 31 | Printful tests + integration testing | 24-30 | 4.5h | |
+| ~~31~~ | ~~Printful + Printify client tests with Req.Test stubs~~ | 24-30 | 4.5h | done |
 | | **Setup and launch readiness** ([plan](docs/plans/setup-and-launch.md)) | | | |
 | ~~41~~ | ~~Provider + payment registries~~ | — | 30m | done |
 | ~~42~~ | ~~Make Setup provider-agnostic + add checklist fields~~ | 41 | 45m | done |
@@ -87,7 +87,7 @@ Plans: [admin-redesign.md](docs/plans/admin-redesign.md) | [admin-font-loading.m
 | | **Bugs / polish** | | | |
 | ~~49~~ | ~~Admin font loading + cache miss path resolver ([plan](docs/plans/admin-font-loading.md))~~ | — | 1h | done |
 
-**Total remaining: ~4.5 hours** (Printful tests)
+**All tasks complete.** No remaining work in the task list.
 
 See [css-migration.md](docs/plans/css-migration.md) for full plan with architecture, visual regression testing strategy, and acceptance criteria per phase.
 
@@ -374,7 +374,7 @@ See: [plan](docs/plans/shipping-sync.md) for implementation details
 - [x] `mix bench.sqlite` task with `--prod`, `--scale`, `--pool-size`, `--busy-timeout` options
 - [x] PRAGMA tuning across dev/test/prod: `default_transaction_mode: :immediate`, `journal_size_limit: 64MB`, `custom_pragmas: [mmap_size: 128MB]`
 - [x] Benchmarks confirmed: IMMEDIATE mode eliminates transaction upgrade BUSY errors (0% vs 73-80% failure rate under contention), prod mode 5-12x faster than dev, 300 concurrent mixed requests with zero errors
-- [x] 898 tests total (6 correctness + 3 benchmarks excluded by default)
+- [x] 972 tests total (5 excluded: 3 benchmarks + 2 correctness)
 
 ### Page Editor
 **Status:** Future (Tier 4)
@@ -389,6 +389,7 @@ See: [docs/plans/page-builder.md](docs/plans/page-builder.md) for design
 
 | Feature | Commit | Notes |
 |---------|--------|-------|
+| Printify + Printful client tests | b0aed4c, a45e85e | Req.Test stubs for both HTTP clients, provider integration tests, mockup enricher tests, 972 tests |
 | SQLite production tuning | 162bf4c, 19d8c7d | Concurrency tests, `mix bench.sqlite` task, IMMEDIATE transactions, mmap 128MB, journal_size_limit 64MB, 898 tests |
 | Per-colour images + gallery filtering | 0fe48ba | colour column on product_images, per-colour mockup enrichment, PDP gallery filtering, Printify option filtering, hero colour ordering, 821 tests |
 | Printful catalog colours | 4e19d4c | Fetch hex codes from catalog product API during sync, cached per catalog_product_id |