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/render_test.go

@@ -0,0 +1,40 @@
+package adapter
+
+import "testing"
+
+func TestRenderHTML(t *testing.T) {
+	cases := []struct {
+		name string
+		in   string
+		want string
+	}{
+		{"heading", "# Title\nbody", "<b>Title</b>\nbody"},
+		{"bold", "this is **bold** text", "this is <b>bold</b> text"},
+		{"italic", "this is _italic_ text", "this is <i>italic</i> text"},
+		{"link", "see [the entry](https://example.com/e/1)", `see <a href="https://example.com/e/1">the entry</a>`},
+		{"code", "```go\nfmt.Println(1)\n```", "<pre>fmt.Println(1)</pre>"},
+		{
+			"table",
+			"| a | b |\n|---|---|\n| 1 | 2 |",
+			"a — b\n\n1 — 2",
+		},
+	}
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			got, err := RenderHTML(tc.in)
+			if err != nil {
+				t.Fatalf("RenderHTML(%q): %v", tc.in, err)
+			}
+			if got != tc.want {
+				t.Errorf("RenderHTML(%q) = %q, want %q", tc.in, got, tc.want)
+			}
+		})
+	}
+}
+
+func TestRenderHTMLRejectsRawAngleBrackets(t *testing.T) {
+	_, err := RenderHTML("a <script> tag")
+	if err == nil {
+		t.Fatal("expected an error for raw angle brackets")
+	}
+}