Add unified post storage.

Provide one creation path for roots and replies, recursive thread loading, body-only updates, root listings, and post voting across PostgreSQL and the in-memory test store.

internal/store/migrate_posts_test.go

@@ -9,6 +9,8 @@ import (
 	"testing"
 
 	"github.com/google/uuid"
+
+	"plumber/internal/store/sqlc"
 )
 
 func TestMigratePostsCopiesLegacyData(t *testing.T) {
@@ -47,7 +49,9 @@ func TestMigratePostsCopiesLegacyData(t *testing.T) {
 
 	legacySchema := `
 CREATE TABLE users (
-  id TEXT PRIMARY KEY
+  id TEXT PRIMARY KEY,
+  name TEXT NOT NULL,
+  role TEXT NOT NULL
 );
 CREATE TABLE questions (
   id TEXT PRIMARY KEY,
@@ -76,7 +80,8 @@ CREATE TABLE votes (
 		t.Fatal(err)
 	}
 	if _, err := conn.ExecContext(ctx, `
-INSERT INTO users (id) VALUES ('homeowner'), ('plumber');
+INSERT INTO users (id, name, role)
+VALUES ('homeowner', 'Home Owner', 'user'), ('plumber', 'The Plumber', 'admin');
 INSERT INTO questions (id, author_id, title, body, city, hunt_date, hidden, created_at)
 VALUES ('question-1', 'homeowner', 'Leaky sink', 'It drips.', 'Oakland', '2026-08-26', 0, '2026-08-26T08:00:00Z');
 INSERT INTO answers (question_id, author_id, body, created_at, updated_at)
@@ -183,6 +188,56 @@ INSERT INTO posts (
 )`); err == nil {
 		t.Fatal("reply with root-only title unexpectedly succeeded")
 	}
+
+	queries := sqlc.New(conn)
+	if err := queries.CreatePost(ctx, sqlc.CreatePostParams{
+		ID:        "follow-up",
+		ParentID:  sql.NullString{String: "answer:question-1", Valid: true},
+		AuthorID:  "homeowner",
+		Body:      "It is still dripping.",
+		CreatedAt: "2026-08-26T10:00:00Z",
+		UpdatedAt: "2026-08-26T10:00:00Z",
+	}); err != nil {
+		t.Fatal(err)
+	}
+	thread, err := queries.ListPostThread(ctx, "question-1")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(thread) != 3 ||
+		thread[0].ID != "question-1" ||
+		thread[1].ID != "answer:question-1" ||
+		thread[2].ID != "follow-up" {
+		t.Fatalf("recursive thread = %+v", thread)
+	}
+	if n, err := queries.UpdatePost(ctx, sqlc.UpdatePostParams{
+		ID:        "follow-up",
+		Body:      "The drip continues.",
+		UpdatedAt: "2026-08-26T10:05:00Z",
+	}); err != nil || n != 1 {
+		t.Fatalf("update rows=%d error=%v", n, err)
+	}
+	if n, err := queries.UpsertPostVoteOnVisibleRoot(ctx, sqlc.UpsertPostVoteOnVisibleRootParams{
+		UserID: "plumber",
+		PostID: "question-1",
+		Value:  1,
+	}); err != nil || n != 1 {
+		t.Fatalf("vote rows=%d error=%v", n, err)
+	}
+	roots, err := queries.ListRootPosts(ctx, sqlc.ListRootPostsParams{
+		ViewerID: "plumber",
+		RowLimit: 100,
+		PostDate: "2026-08-26",
+	})
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(roots) != 1 ||
+		roots[0].Score != 2 ||
+		!roots[0].Answered ||
+		roots[0].UserVote != 1 {
+		t.Fatalf("root annotations = %+v", roots)
+	}
 }
 
 func TestMigratePostsReportsStep(t *testing.T) {