refactor: move block scanning logic to shared module

Import `FENCED_BLOCK_RE` and `parseBlockAttrs` from `block-scanner.js`
instead of defining them locally in `declare-parser.ts`.

src/cli/completions/declare-parser.ts

@@ -15,25 +15,7 @@
  */
 
 import { parse } from "csv-parse/browser/esm/sync";
-
+import { FENCED_BLOCK_RE, parseBlockAttrs } from "./block-scanner.js";
-// ---------------------------------------------------------------------------
-// Shared block scanning — used by both CLI (block-processor) and client
-// (completions.ts) so there's a single source of truth for declare parsing.
-// ---------------------------------------------------------------------------
-
-/** Matches fenced code blocks with an info string. */
-const FENCED_BLOCK_RE = /^```(\w*)\s+(\S.*?)\s*\n([\s\S]*?)```\s*$/gm;
-
-/** Parse key="value" and key=value pairs from an attribute string. */
-function parseBlockAttrs(info: string): Record<string, string> {
-  const attrs: Record<string, string> = {};
-  const re = /(\w+)\s*=\s*("[^"]*"|\S+)/g;
-  let m: RegExpExecArray | null;
-  while ((m = re.exec(info)) !== null) {
-    attrs[m[1]] = m[2].replace(/^"|"$/g, "");
-  }
-  return attrs;
-}
 
 /**
  * Scan markdown content for ```csv role=declare blocks and return