Implement the R-1 adapter (FT-WP-0001 T05/T09); mark workplans blocked

Builds internal/adapter and cmd/adapter: the three contracts/r1.openapi.yaml
operations, idempotency on post_id, the reviewed_by/consent-basis refusals,
per-form (R-2/R-3) length limits, and Markdown-to-Telegram rendering, all
against a Sender interface so it's testable without a live bot token.

Every other open task in FT-WP-0001 and FT-WP-0002 needs something this repo
can't supply on its own: the human session bootstrap in FT-WP-0002 T01, the
fluid CLI from fluid-core, or a person's judgment (consent basis, editorial
review, publishing pace). Set both workplans to status: blocked and flagged
FT-WP-0002-T01 needs_human on the hub, since it's the single blocker gating
everything else.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

Assistant: claude-code
Assistant-Model: sonnet
Assistant-Process: 278411@bnt-lap001
Assistant-Session: 19568045-15bc-4b88-ba3d-8e95b4f9c6f1

internal/adapter/telemetry.go

@@ -0,0 +1,46 @@
+package adapter
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"net/http"
+	"time"
+)
+
+// HTTPTelemetry POSTs to the control plane, per docs/adapter-contract.md.
+// It must never carry subscriber identity or post body text; callers control
+// that by what they put in fields.
+type HTTPTelemetry struct {
+	ControlURL string
+	hc         *http.Client
+}
+
+// NewHTTPTelemetry builds a telemetry emitter posting to
+// <controlURL>/control/v1/telemetry.
+func NewHTTPTelemetry(controlURL string) *HTTPTelemetry {
+	return &HTTPTelemetry{ControlURL: controlURL, hc: &http.Client{Timeout: 10 * time.Second}}
+}
+
+func (t *HTTPTelemetry) Emit(ctx context.Context, event string, fields map[string]any) {
+	if t.ControlURL == "" {
+		return
+	}
+	payload := map[string]any{"event": event, "fields": fields}
+	body, err := json.Marshal(payload)
+	if err != nil {
+		return
+	}
+	req, err := http.NewRequestWithContext(ctx, http.MethodPost, t.ControlURL+"/control/v1/telemetry", bytes.NewReader(body))
+	if err != nil {
+		return
+	}
+	req.Header.Set("Content-Type", "application/json")
+	// Best-effort: a dropped telemetry event must never fail the publication
+	// it describes.
+	resp, err := t.hc.Do(req)
+	if err != nil {
+		return
+	}
+	_ = resp.Body.Close()
+}