Story 26: Establish TDD workflow and quality gates

Add workflow engine with acceptance gates, test recording, and review
queue. Frontend displays gate status (blocked/ready), test summaries,
failing badges, and warnings. Proceed action is disabled when gates
are not met. Includes 13 unit tests (Vitest) and 9 E2E tests
(Playwright) covering all five acceptance criteria.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

server/src/io/story_metadata.rs

@@ -0,0 +1,111 @@
+use serde::Deserialize;
+
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub enum TestPlanStatus {
+    Approved,
+    WaitingForApproval,
+    Unknown(String),
+}
+
+#[derive(Debug, Clone, PartialEq, Eq, Default)]
+pub struct StoryMetadata {
+    pub name: Option<String>,
+    pub test_plan: Option<TestPlanStatus>,
+}
+
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub enum StoryMetaError {
+    MissingFrontMatter,
+    InvalidFrontMatter(String),
+}
+
+#[derive(Debug, Deserialize)]
+struct FrontMatter {
+    name: Option<String>,
+    test_plan: Option<String>,
+}
+
+pub fn parse_front_matter(contents: &str) -> Result<StoryMetadata, StoryMetaError> {
+    let mut lines = contents.lines();
+
+    let first = lines.next().unwrap_or_default().trim();
+    if first != "---" {
+        return Err(StoryMetaError::MissingFrontMatter);
+    }
+
+    let mut front_lines = Vec::new();
+    for line in &mut lines {
+        let trimmed = line.trim();
+        if trimmed == "---" {
+            let raw = front_lines.join("\n");
+            let front: FrontMatter = serde_yaml::from_str(&raw)
+                .map_err(|e| StoryMetaError::InvalidFrontMatter(e.to_string()))?;
+            return Ok(build_metadata(front));
+        }
+        front_lines.push(line);
+    }
+
+    Err(StoryMetaError::InvalidFrontMatter(
+        "Missing closing front matter delimiter".to_string(),
+    ))
+}
+
+fn build_metadata(front: FrontMatter) -> StoryMetadata {
+    let test_plan = front.test_plan.as_deref().map(parse_test_plan_status);
+
+    StoryMetadata {
+        name: front.name,
+        test_plan,
+    }
+}
+
+fn parse_test_plan_status(value: &str) -> TestPlanStatus {
+    match value {
+        "approved" => TestPlanStatus::Approved,
+        "waiting_for_approval" => TestPlanStatus::WaitingForApproval,
+        other => TestPlanStatus::Unknown(other.to_string()),
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn parses_front_matter_metadata() {
+        let input = r#"---
+name: Establish the TDD Workflow and Gates
+test_plan: approved
+workflow: tdd
+---
+# Story 26
+"#;
+
+        let meta = parse_front_matter(input).expect("front matter");
+        assert_eq!(
+            meta,
+            StoryMetadata {
+                name: Some("Establish the TDD Workflow and Gates".to_string()),
+                test_plan: Some(TestPlanStatus::Approved),
+            }
+        );
+    }
+
+    #[test]
+    fn rejects_missing_front_matter() {
+        let input = "# Story 26\n";
+        assert_eq!(
+            parse_front_matter(input),
+            Err(StoryMetaError::MissingFrontMatter)
+        );
+    }
+
+    #[test]
+    fn rejects_unclosed_front_matter() {
+        let input = "---\nname: Test\n";
+        assert!(matches!(
+            parse_front_matter(input),
+            Err(StoryMetaError::InvalidFrontMatter(_))
+        ));
+    }
+}