content: add Content.ListPosts capability for blog listing

Adds ListPosts(ctx, ListPostsParams) to the content.Content capability so
wasm plugins can list posts with bodies — the per-plugin Postgres role
denies direct public.blog_posts reads (42501) and GetPost only fetches a
single post's metadata. Extends PostInfo with Body, AuthorName, AuthorSlug
and PublishedAt (additive; existing get_post golden unchanged). Wires all
layers: interface, ABI PostInfo/ContentListPosts{Request,Response} messages
(buf breaking clean), guest stub, and a deterministic content_list_posts
golden replayed by the cms host parity test.

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

abi/proto/v1/capability.proto

@@ -98,6 +98,23 @@ message PostInfo {
   string excerpt = 4;
   string featured_image_url = 5;
   string author_id = 6; // UUID
+  string body = 7; // rendered HTML; set by get_post / list_posts(include_body)
+  string author_name = 8;
+  string author_slug = 9;
+  google.protobuf.Timestamp published_at = 10;
+}
+
+message ContentListPostsRequest {
+  int32 limit = 1;
+  int32 offset = 2;
+  string category = 3; // optional category slug filter ("" = all)
+  bool published_only = 4;
+  bool include_body = 5;
+  bool include_excerpt = 6;
+}
+
+message ContentListPostsResponse {
+  repeated PostInfo posts = 1;
 }
 
 message ContentSlugifyRequest {

content/content.go

@@ -2,6 +2,7 @@ package content
 
 import (
 	"context"
+	"time"
 
 	"github.com/google/uuid"
 )
@@ -24,14 +25,33 @@ type PageInfo struct {
 	Title string
 }
 
-// PostInfo is a simplified post representation for plugins.
+// PostInfo is a simplified post representation for plugins. It carries enough
+// for both a blog index (title/slug/excerpt/author/date/featured image) and a
+// post detail view (Body — the rendered HTML). Body is populated by GetPost and
+// by ListPosts when ListPostsParams.IncludeBody is set; it is empty otherwise.
 type PostInfo struct {
 	ID               uuid.UUID
 	Slug             string
 	Title            string
 	Excerpt          string
+	Body             string // rendered HTML; populated by GetPost / ListPosts(IncludeBody)
 	FeaturedImageURL string
 	AuthorID         uuid.UUID
+	AuthorName       string
+	AuthorSlug       string
+	PublishedAt      time.Time
+}
+
+// ListPostsParams filters and shapes a ListPosts query. The zero value lists
+// published posts from the start with no category filter, excerpts included and
+// bodies omitted (the cheap blog-index shape).
+type ListPostsParams struct {
+	Limit          int    // 0 = host default
+	Offset         int    // pagination offset
+	Category       string // optional category slug filter ("" = all)
+	PublishedOnly  bool   // reserved: plugins only ever see published posts
+	IncludeBody    bool   // render each post's body to HTML (expensive)
+	IncludeExcerpt bool   // include the post excerpt
 }
 
 // Content provides content access for plugins.
@@ -40,6 +60,7 @@ type Content interface {
 	GetAuthorProfile(ctx context.Context, id uuid.UUID) (*AuthorProfile, error)
 	GetPage(ctx context.Context, slug string) (*PageInfo, error)
 	GetPost(ctx context.Context, slug string) (*PostInfo, error)
+	ListPosts(ctx context.Context, params ListPostsParams) ([]PostInfo, error)
 	Slugify(text string) string
 	BlockNoteToHTML(ctx context.Context, doc map[string]any) string
 	GenerateExcerpt(html string, maxLen int) string

plugin/wasmguest/caps/caps_roundtrip_test.go

@@ -12,6 +12,7 @@ import (
 
 	abiv1 "git.dev.alexdunmow.com/block/core/abi/v1"
 	"git.dev.alexdunmow.com/block/core/ai"
+	"git.dev.alexdunmow.com/block/core/content"
 	"git.dev.alexdunmow.com/block/core/gating"
 	"git.dev.alexdunmow.com/block/core/plugin"
 	"github.com/google/uuid"
@@ -188,6 +189,33 @@ func TestCapabilityRoundTrip(t *testing.T) {
 				}
 			},
 		},
+		{
+			name: "content_list_posts", wantMethod: "content.list_posts",
+			resp: &abiv1.ContentListPostsResponse{Posts: []*abiv1.PostInfo{
+				{
+					Id: idAuthor.String(), Slug: "first", Title: "First", Excerpt: "one",
+					FeaturedImageUrl: "media:1", AuthorId: idAuthor.String(),
+					AuthorName: "Ada", AuthorSlug: "ada", PublishedAt: timestamppb.New(planTime),
+				},
+				{
+					Id: idPlan.String(), Slug: "second", Title: "Second", Excerpt: "two",
+					AuthorId: idAuthor.String(), AuthorName: "Ada", AuthorSlug: "ada",
+					PublishedAt: timestamppb.New(planTime),
+				},
+			}},
+			run: func(t *testing.T, cs plugin.CoreServices) {
+				got, err := cs.Content.ListPosts(ctx, content.ListPostsParams{Limit: 10, IncludeExcerpt: true})
+				if err != nil {
+					t.Fatal(err)
+				}
+				if len(got) != 2 || got[0].Slug != "first" || got[0].AuthorName != "Ada" {
+					t.Fatalf("posts = %+v", got)
+				}
+				if got[1].Slug != "second" || !got[1].PublishedAt.Equal(planTime) {
+					t.Errorf("post[1] = %+v", got[1])
+				}
+			},
+		},
 		{
 			name: "content_slugify", wantMethod: "content.slugify",
 			resp: &abiv1.ContentSlugifyResponse{Slug: "hello-world"},

plugin/wasmguest/caps/content.go

@@ -3,6 +3,7 @@ package caps
 import (
 	"context"
 	"encoding/json"
+	"time"
 
 	abiv1 "git.dev.alexdunmow.com/block/core/abi/v1"
 	"git.dev.alexdunmow.com/block/core/content"
@@ -55,14 +56,49 @@ func (s *contentStub) GetPost(ctx context.Context, slug string) (*content.PostIn
 	if p == nil {
 		return nil, nil
 	}
-	return &content.PostInfo{
+	info := postInfoFromProto(p)
+	return &info, nil
+}
+
+func (s *contentStub) ListPosts(ctx context.Context, params content.ListPostsParams) ([]content.PostInfo, error) {
+	req := &abiv1.ContentListPostsRequest{
+		Limit:          int32(params.Limit),
+		Offset:         int32(params.Offset),
+		Category:       params.Category,
+		PublishedOnly:  params.PublishedOnly,
+		IncludeBody:    params.IncludeBody,
+		IncludeExcerpt: params.IncludeExcerpt,
+	}
+	resp := &abiv1.ContentListPostsResponse{}
+	if err := s.invoke(ctx, "list_posts", req, resp); err != nil {
+		return nil, err
+	}
+	out := make([]content.PostInfo, 0, len(resp.GetPosts()))
+	for _, p := range resp.GetPosts() {
+		out = append(out, postInfoFromProto(p))
+	}
+	return out, nil
+}
+
+// postInfoFromProto decodes an abiv1.PostInfo into the SDK content.PostInfo,
+// shared by GetPost and ListPosts.
+func postInfoFromProto(p *abiv1.PostInfo) content.PostInfo {
+	var publishedAt time.Time
+	if ts := p.GetPublishedAt(); ts != nil {
+		publishedAt = ts.AsTime()
+	}
+	return content.PostInfo{
 		ID:               parseUUID(p.GetId()),
 		Slug:             p.GetSlug(),
 		Title:            p.GetTitle(),
 		Excerpt:          p.GetExcerpt(),
+		Body:             p.GetBody(),
 		FeaturedImageURL: p.GetFeaturedImageUrl(),
 		AuthorID:         parseUUID(p.GetAuthorId()),
-	}, nil
+		AuthorName:       p.GetAuthorName(),
+		AuthorSlug:       p.GetAuthorSlug(),
+		PublishedAt:      publishedAt,
+	}
 }
 
 // Slugify has no error channel in the interface; a transport failure degrades

plugin/wasmguest/caps/testdata/golden/content_list_posts_req.pb

@@ -0,0 +1,2 @@
+
+0

plugin/wasmguest/caps/testdata/golden/content_list_posts_resp.pb

@@ -0,0 +1,5 @@
+
+z
+$22222222-2222-2222-2222-222222222222firstFirst"one*media:12$22222222-2222-2222-2222-222222222222BAdaJadaRÀÈžÒ
+s
+$88888888-8888-8888-8888-888888888888secondSecond"two2$22222222-2222-2222-2222-222222222222BAdaJadaRÀÈžÒ