Fix medium-severity spec drift across 17 specs

- authentication-methods: document completeAuth mode param ("redirect"|"json");
  clarify add-passkey nudge (no dismiss mechanism, disappears on passkey add)
- journal-auth: session maxAge is 30 days; terms allow-list uses /legal/ prefix
  matching (broader than fixed list of paths)
- session-notes: mark awareness isolation and UndoManager isolation as not yet
  implemented (shared instances in current code)
- activity-feed: add fan-out scenario for visibility change to public
- explore: note that ?perPage is not yet implemented (hardcoded page size)
- multi-day-routes: add per-day GPX track split scenario (splitByDays option);
  document overnight vs isDayBreak naming gap
- osm-poi-overlays: debounce is 800ms + 2000ms min interval (not 500ms);
  retry is not automatic (fires on next viewport change)
- brouter-integration: rate limit corrected to 300/hour; add segment-cache
  requirement (client caches per-pair segments)
- wahoo-route-push: OAuth state shape uses camelCase (returnTo, pushAfter
  object) not snake_case with push_after boolean
- komoot-import: document noop adapter / ConnectedServiceManager bypass;
  note four Komoot-specific routes that bypass the generic OAuth framework
- background-jobs: exponential backoff not wired (retryLimit only); add SIGINT
- connected-services: add revoked status; name ConnectionNotActiveError
- infrastructure: add INTEGRATION_SECRET and SENTRY_DSN to env var lists;
  split secret decryption scenario by workflow (cd-apps vs cd-infra)
- secret-management: correct CD decryption — cd-apps only decrypts app.env;
  cd-infra decrypts both
- transactional-emails: welcome email is async (pg-boss job); magic-link email
  includes 6-digit numeric code
- journal-route-detail: websites are https: links (not mailto:); opening_hours
  is also displayed
- local-dev-environment: add mobile app (Expo) dev commands

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

openspec/specs/transactional-emails/spec.md

@@ -24,14 +24,14 @@ The system SHALL send an email containing the magic link when a user requests pa
 
 #### Scenario: Email content
 - **WHEN** a magic link email is sent
-- **THEN** it includes: the link, expiry time (15 minutes), and plain-text fallback
+- **THEN** it includes: the clickable link, a prominently displayed 6-digit numeric code (for users who prefer copy-paste over clicking), expiry time (15 minutes), and a plain-text fallback
 
 ### Requirement: Welcome email
-The system SHALL send a welcome email after successful registration.
+The system SHALL send a welcome email after successful registration. The welcome email is sent asynchronously via a pg-boss `send-welcome-email` job rather than inline during the registration request.
 
 #### Scenario: Welcome on registration
-- **WHEN** a user completes passkey registration
-- **THEN** a welcome email is sent to their registered email address
+- **WHEN** a user completes registration (passkey or magic-link)
+- **THEN** a `send-welcome-email` job is enqueued and the email is delivered asynchronously to their registered email address
 
 ### Requirement: Email templates
 Each email type SHALL have an HTML template with a plain-text fallback.