refactor: remove as= override and render data-spark at runtime

- Drop resolveBlockAs and the as= attribute; scanDoc now switches
  directly on role and warns on unknown roles instead of silently
  stripping
- md-table derives data-spark from its loaded CSV via
  parseSparkTableCsv; delete injectSparkDirectives and the second
  registry pass so pathIndex is exactly scanDoc output
- Align spark-table dice header regex with isSparkTableHeader

src/cli/completions/block-scanner.ts

@@ -2,11 +2,15 @@
  * Shared block scanning utilities — safe for both CLI and browser.
  *
  * Parses fenced code blocks with attributes:
- *   ```lang id=xxx role=xxx as=xxx
+ *   ```lang id=xxx role=xxx key=value
  *
- * - `role` dispatches to content scanners (declare, spark-table)
- * - `as` controls rendering (none, codeblock, md-table, md-card, md-dice)
- * - `id` is used for cross-references (file paths)
+ * The `role` fully determines block behavior (see `scanDoc` in
+ * `content-registry.ts`):
+ *   - spark-table → stored as CSV, rendered as an `:md-table` directive
+ *   - declare / file → stored, block stripped
+ *   - tag → block kept intact for the yaml-tag render extension
+ *   - unknown role → warned about and stripped
+ *   - no role → kept as a visible code block
  *
  * Attribute parsing itself lives in `src/markdown/block-attrs.ts` so render
  * extensions can share the same syntax.
@@ -19,28 +23,4 @@ export { parseBlockAttrs, type BlockAttrs } from "../../markdown/block-attrs.js"
 // ---------------------------------------------------------------------------
 
 /** Matches fenced code blocks with an info string (at least one attr). */
-export const FENCED_BLOCK_RE = /^```(\w*)\s+(\S.*?)\s*\n([\s\S]*?)```\s*$/gm;
-
-// ---------------------------------------------------------------------------
-// as resolution
-// ---------------------------------------------------------------------------
-
-/**
- * Determine the effective `as` value.
- *
- * Defaults:
- *   - role is set, no explicit as → "none" (strip — it's metadata)
- *   - role=spark-table → "md-table" (render as md-table directive)
- *   - role=tag → "codeblock" (kept for the marked yaml-tag extension)
- *   - no role, no as → "codeblock" (keep as visible code block)
- */
-export function resolveBlockAs(role: string | undefined, as: string | undefined): string {
-  if (as) return as;
-  // spark-table blocks render as md-table by default
-  if (role === "spark-table") return "md-table";
-  // yaml-defined tag blocks must survive stripping so the
-  // code-block-yaml-tag marked extension can render them
-  if (role === "tag") return "codeblock";
-  if (role) return "none";
-  return "codeblock";
-}
+export const FENCED_BLOCK_RE = /^```(\w*)\s+(\S.*?)\s*\n([\s\S]*?)```\s*$/gm;

src/cli/completions/variable-system.test.ts

@@ -28,7 +28,7 @@ jest.mock("github-slugger", () => {
 // ---------------------------------------------------------------------------
 
 import { parseDeclareCsv } from "./declare-parser";
-import { parseBlockAttrs, resolveBlockAs } from "./block-scanner";
+import { parseBlockAttrs } from "./block-scanner";
 import { evaluateExpression, exprValueToString } from "../../components/journal/variable-expression";
 import {
   initReactivity,
@@ -220,10 +220,9 @@ describe("parseBlockAttrs", () => {
     // parseBlockAttrs receives the info string AFTER the lang.
     // The lang is extracted from the fenced block regex capture group
     // and applied separately in content-registry.
-    const attrs = parseBlockAttrs("id=stats role=declare as=none");
+    const attrs = parseBlockAttrs("id=stats role=declare");
     expect(attrs.id).toBe("stats");
     expect(attrs.role).toBe("declare");
-    expect(attrs.as).toBe("none");
   });
 
   test("parses quoted values", () => {
@@ -242,7 +241,6 @@ describe("parseBlockAttrs", () => {
     expect(attrs.lang).toBe("");
     expect(attrs.id).toBeUndefined();
     expect(attrs.role).toBeUndefined();
-    expect(attrs.as).toBeUndefined();
   });
 
   test("handles empty info string (lang extracted separately)", () => {
@@ -252,28 +250,8 @@ describe("parseBlockAttrs", () => {
   });
 });
 
-describe("resolveBlockAs", () => {
-  test("returns explicit as value", () => {
-    expect(resolveBlockAs("declare", "codeblock")).toBe("codeblock");
-  });
-
-  test("defaults to none when role is set", () => {
-    expect(resolveBlockAs("declare", undefined)).toBe("none");
-    expect(resolveBlockAs("file", undefined)).toBe("none");
-  });
-
-  test("defaults to md-table for spark-table role", () => {
-    expect(resolveBlockAs("spark-table", undefined)).toBe("md-table");
-  });
-
-  test("defaults to codeblock for tag role", () => {
-    expect(resolveBlockAs("tag", undefined)).toBe("codeblock");
-  });
-
-  test("defaults to codeblock when no role and no as", () => {
-    expect(resolveBlockAs(undefined, undefined)).toBe("codeblock");
-  });
-});
+// Role behavior is covered by the scanDoc tests in
+// src/cli/content-registry.test.ts.
 
 // ---------------------------------------------------------------------------
 // variable-expression