fix(sdd): ignore fenced Markdown examples

Task counters and clarification parsers previously only checked for
unindented triple-backtick fences. Markdown examples inside tilde fences
or indented code blocks were incorrectly counted as active tasks or
clarification questions. Advance fence state across CommonMark fences.

Signed-off-by: 1fanwang <1fannnw@gmail.com>

Author: 1fanwang

plugins/spec-kit-copilot-sdd/extensions/sdd-canvas/sdd.mjs

@@ -252,18 +252,35 @@ function constitutionStatus(text) {
     return placeholders > 0 ? "template" : "ratified";
 }
 
+function advanceMarkdownFence(line, openFence) {
+    const match = line.match(/^ {0,3}(`{3,}|~{3,})(.*)$/);
+    if (!match) return { openFence, isFenceLine: false };
+
+    const marker = match[1][0];
+    const length = match[1].length;
+    const rest = match[2];
+    if (!openFence) {
+        if (marker === "`" && rest.includes("`")) {
+            return { openFence: null, isFenceLine: false };
+        }
+        return { openFence: { marker, length }, isFenceLine: true };
+    }
+    if (marker === openFence.marker && length >= openFence.length && !rest.trim()) {
+        return { openFence: null, isFenceLine: true };
+    }
+    return { openFence, isFenceLine: false };
+}
+
 // Count task checkboxes in tasks.md to derive implementation progress.
-function taskProgress(text) {
+export function taskProgress(text) {
     if (typeof text !== "string") return { total: 0, completed: 0 };
     let total = 0;
     let completed = 0;
-    let inFence = false;
+    let openFence = null;
     for (const line of text.split(/\r?\n/)) {
-        if (line.startsWith("```")) {
-            inFence = !inFence;
-            continue;
-        }
-        if (inFence) continue;
+        const fenceState = advanceMarkdownFence(line, openFence);
+        openFence = fenceState.openFence;
+        if (fenceState.isFenceLine || openFence) continue;
         const m = line.match(/^\s*[-*+]\s+\[([ xX])\]/);
         if (!m) continue;
         total++;
@@ -519,13 +536,11 @@ export function readArtifact(projectRoot, featureInput, stageKey) {
 export function extractClarifications(text) {
     const clarifications = [];
     let section = "";
-    let inCodeFence = false;
+    let openFence = null;
     for (const line of String(text || "").split(/\r?\n/)) {
-        if (line.startsWith("```")) {
-            inCodeFence = !inCodeFence;
-            continue;
-        }
-        if (inCodeFence) continue;
+        const fenceState = advanceMarkdownFence(line, openFence);
+        openFence = fenceState.openFence;
+        if (fenceState.isFenceLine || openFence) continue;
         const heading = line.match(/^#{1,6}\s+(.+?)\s*$/);
         if (heading) {
             section = heading[1].trim();

plugins/spec-kit-copilot-sdd/extensions/sdd-canvas/tests/sdd.test.mjs

@@ -23,6 +23,9 @@ test("implementation progress scans the complete bounded tasks artifact", (t) =>
     write(join(featureDir, "plan.md"), "# Plan\n", 2);
     const tasks = [
         "# Tasks",
+        "~~~markdown",
+        "- [x] T000 Example only",
+        "~~~",
         "- [x] T001 Complete near the start",
         "padding".repeat(10_000),
         "- [ ] T002 Incomplete after the 64 KiB scan prefix",
@@ -51,6 +54,9 @@ test("clarifications retain stable indices across supported markdown blocks", ()
         "```text",
         "[NEEDS CLARIFICATION: Ignore code?]",
         "```",
+        "   ~~~markdown",
+        "[NEEDS CLARIFICATION: Ignore indented tilde fence?]",
+        "   ~~~",
     ].join("\n");
 
     assert.deepEqual(extractClarifications(markdown), [