Phase 7: daily summary and read-only Hub API (AUD-73)

- internal/hub: project side of the frozen ask-contract. GET /capabilities,
  read-only POST /ask answerer (no LLM, <3s), and the outbound POST /notify
  client.
- internal/apprise: daily-summary delivery through the house Apprise API.
- internal/summary: deterministic plain-text daily summary builder.
- internal/store: CountByCategory, MessagesByCategory, and summary CRUD.
- internal/server: /capabilities and /ask (bearer-token protected), plus the
  Reports screen (/reports, build, send, delete).
- main.go: -summary, -summary-send, and -notify CLI entry points for n8n.

Co-Authored-By: Paperclip <noreply@paperclip.ing>

web/templates/dashboard.html

@@ -28,6 +28,7 @@
     <div class="nav-actions">
       <a class="btn btn-utility" href="/rules">Rules</a>
       <a class="btn btn-utility" href="/unsubscribe">Unsubscribe</a>
+      <a class="btn btn-utility" href="/reports">Reports</a>
       <button class="btn btn-utility theme-toggle" type="button" onclick="eaToggleTheme()" aria-label="Toggle dark mode">
         <span class="icon-light" aria-hidden="true">&#9790;</span>
         <span class="icon-dark" aria-hidden="true">&#9728;</span>