refactor: move spark table parsing to directive scanner

Relocate spark table logic from the block processor to a dedicated
directive scanner. This allows spark tables to be treated as
`:md-table` directives and ensures they are processed in a second pass
after the content index is fully populated.

src/cli/completions/block-scanner.ts

@@ -9,9 +9,6 @@
  * - `id` is used for cross-references (template names, file paths)
  */
 
-import Slugger from "github-slugger";
-import type { SparkTableCompletion } from "./types.js";
-
 // ---------------------------------------------------------------------------
 // Types
 // ---------------------------------------------------------------------------
@@ -58,46 +55,13 @@ export function parseBlockAttrs(info: string): BlockAttrs {
  *
  * Defaults:
  *   - role is set, no explicit as → "none" (strip — it's metadata)
+ *   - role=spark-table → "md-table" (render as md-table directive)
  *   - no role, no as → "codeblock" (keep as visible code block)
  */
 export function resolveBlockAs(role: string | undefined, as: string | undefined): string {
   if (as) return as;
+  // spark-table blocks render as md-table by default
+  if (role === "spark-table") return "md-table";
   if (role) return "none";
   return "codeblock";
-}
-
-// ---------------------------------------------------------------------------
-// Spark table parsing
-// ---------------------------------------------------------------------------
-
-const DICE_RE = /^d\d+$/i;
-
-export function parseSparkTableCsv(
-  body: string,
-  filePath: string,
-  slugger: Slugger,
-): SparkTableCompletion | null {
-  const lines = body.trim().split(/\r?\n/);
-  if (lines.length < 2) return null;
-
-  const headers = lines[0].split(",").map((h) => h.trim());
-  if (headers.length < 2) return null;
-  if (!DICE_RE.test(headers[0])) return null;
-
-  const dataHeaders = headers.slice(1);
-  const slug = dataHeaders
-    .map((h) => slugger.slug(h.toLowerCase()))
-    .join("-");
-
-  const basePath = filePath.replace(/\.md$/, "");
-  const fileName = basePath.split("/").filter(Boolean).pop() || basePath;
-  const combinedSlug = `${fileName}-${slug}`;
-
-  return {
-    label: `${fileName} § ${slug}`,
-    notation: headers[0],
-    slug: combinedSlug,
-    filePath: basePath,
-    headers: dataHeaders,
-  };
-}
+}