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>

internal/hub/notify.go

@@ -0,0 +1,104 @@
+// Outbound notify path (ask-contract.md, "Notify (project to Hub)").
+//
+// A project may tell the Hub something so the Hub can speak or notify. This is
+// the one call this service makes into the Hub. It is best-effort: the Hub's
+// /notify receiver is not part of its frozen v1 routes (docs/hub-api.md §12),
+// so a failure is logged and never blocks the local work.
+package hub
+
+import (
+	"bytes"
+	"context"
+	"fmt"
+	"net/http"
+	"strings"
+	"time"
+)
+
+// Notifier posts project notifications to the Hub. The nil zero value is not
+// usable; build one with NewNotifier.
+type Notifier struct {
+	BaseURL string
+	Token   string
+	HTTP    *http.Client
+}
+
+// NewNotifier builds a notifier for the Hub at baseURL. timeout defaults to
+// five seconds when it is zero or negative.
+func NewNotifier(baseURL, token string, timeout time.Duration, httpClient *http.Client) *Notifier {
+	if timeout <= 0 {
+		timeout = 5 * time.Second
+	}
+	if httpClient == nil {
+		httpClient = &http.Client{Timeout: timeout}
+	}
+	return &Notifier{
+		BaseURL: strings.TrimRight(baseURL, "/"),
+		Token:   token,
+		HTTP:    httpClient,
+	}
+}
+
+// Configured reports whether the outbound notify path can be attempted.
+func (n *Notifier) Configured() bool {
+	return n != nil && strings.TrimSpace(n.BaseURL) != ""
+}
+
+// Notify posts one notification. A nil notifier is a no-op so callers do not
+// need to branch on configuration.
+func (n *Notifier) Notify(ctx context.Context, req NotifyRequest) error {
+	if !n.Configured() {
+		return fmt.Errorf("hub notify is not configured")
+	}
+	if strings.TrimSpace(req.From) == "" {
+		req.From = ProjectName
+	}
+	body, err := jsonBody(req)
+	if err != nil {
+		return fmt.Errorf("encode notify: %w", err)
+	}
+	url := n.BaseURL + "/notify"
+	httpReq, err := http.NewRequestWithContext(ctx, http.MethodPost, url, bytes.NewReader(body))
+	if err != nil {
+		return fmt.Errorf("build notify request: %w", err)
+	}
+	httpReq.Header.Set("Content-Type", "application/json; charset=utf-8")
+	if n.Token != "" {
+		httpReq.Header.Set("Authorization", "Bearer "+n.Token)
+	}
+
+	resp, err := n.HTTP.Do(httpReq)
+	if err != nil {
+		return fmt.Errorf("post notify: %w", err)
+	}
+	defer resp.Body.Close()
+	if resp.StatusCode < 200 || resp.StatusCode >= 300 {
+		return fmt.Errorf("post notify: status %d", resp.StatusCode)
+	}
+	return nil
+}
+
+// NotifySummaryReady is the convenience call used after a daily summary is
+// built.
+func (n *Notifier) NotifySummaryReady(ctx context.Context, message string) error {
+	return n.Notify(ctx, NotifyRequest{
+		From:    ProjectName,
+		Level:   "info",
+		Message: message,
+		Person:  "sam",
+	})
+}
+
+// NotifyImportantCount tells the Hub how many messages need attention. It is
+// used by the daily summary job when the count is non-zero.
+func (n *Notifier) NotifyImportantCount(ctx context.Context, n2 int) error {
+	if n2 <= 0 {
+		return nil
+	}
+	return n.Notify(ctx, NotifyRequest{
+		From:    ProjectName,
+		Level:   "important",
+		Message: fmt.Sprintf("%d emails need a decision.", n2),
+		Person:  "sam",
+	})
+}