feat(outreach): admin outreach pipeline + separate sending domain (all subtasks)

Adds cold B2B supplier outreach pipeline isolated from transactional emails.

Subtask 1 — Migration + constants:
- Migration 0024: 4 new columns on suppliers (outreach_status, outreach_notes,
  last_contacted_at, outreach_sequence_step); NULL status = not in pipeline
- EMAIL_ADDRESSES["outreach"] = hello.padelnomics.io (separate reputation domain)
- "outreach" added to EMAIL_TYPES

Subtask 2 — Query functions + routes:
- get_outreach_pipeline() — counts by status for pipeline cards
- get_outreach_suppliers() — filtered list with status/country/search
- GET /admin/outreach — pipeline dashboard
- GET /admin/outreach/results — HTMX partial
- POST /admin/outreach/<id>/status — inline status update
- POST /admin/outreach/<id>/note — inline note edit
- POST /admin/outreach/add-prospects — bulk set from supplier list

Subtask 3 — CSV import:
- GET/POST /admin/outreach/import
- Accepts name+contact_email (required), country_code/category/website (optional)
- Deduplicates by contact_email, auto-generates slug, capped at 500 rows

Subtask 4 — Templates:
- outreach.html (pipeline cards + HTMX filter + results table)
- outreach_import.html (CSV upload form)
- partials/outreach_results.html, partials/outreach_row.html
- base_admin.html: Outreach sidebar link
- suppliers.html + supplier_results.html: checkbox column + bulk action bar

Subtask 5 — Compose integration:
- email_compose() GET: ?from_key=outreach&email_type=outreach&supplier_id=<id>
  pre-fills from-addr, stores hidden fields, defaults wrap=0 (plain text)
- email_compose() POST: on outreach send, advances prospect→contacted,
  increments outreach_sequence_step, sets last_contacted_at
- email_compose.html: hidden email_type + supplier_id fields, outreach banner
- supplier_detail.html: outreach card (status, step, last contact, send button)

Subtask 6 — Tests:
- 44 tests in web/tests/test_outreach.py covering: constants, access control,
  query functions, dashboard, HTMX partial, status update, note update,
  add-prospects, CSV import, compose pre-fill, compose pipeline update

Subtask 7 — Docs:
- CHANGELOG.md and PROJECT.md updated

Manual step after deploy: add hello.padelnomics.io in Resend dashboard + DNS.

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

PROJECT.md

@@ -113,6 +113,7 @@
 - [x] **Marketplace admin dashboard** (`/admin/marketplace`) — lead funnel, credit economy, supplier engagement, live activity stream, inline feature flag toggles
 - [x] **Lead matching notifications** — `notify_matching_suppliers` task on quote verification + `send_weekly_lead_digest` every Monday; one-click CTA token in forward emails
 - [x] **Migration 0022** — `status_updated_at`, `supplier_note`, `cta_token` on `lead_forwards`; supplier respond endpoint; inline HTMX lead detail actions; extended quote form fields
+- [x] **Outreach pipeline** (`/admin/outreach`) — cold B2B supplier outreach with separate sending domain (`hello.padelnomics.io`), 6-stage pipeline cards, HTMX inline status + note editing, CSV import, bulk add-to-pipeline from supplier list, compose integration (auto-updates pipeline on send); migration 0024 adds 4 outreach columns to suppliers; 44 tests
 
 ### SEO & Legal
 - [x] Sitemap (both language variants, `<lastmod>` on all entries)