feat(nbd): render tickets as TOML frontmatter markdown [4036aa]

Replace the key-value table format with TOML frontmatter + body when
printing tickets to stdout (nbd read, nbd create, nbd archive, nbd next
— all non-JSON paths). The --json output is unchanged.

New format:
  +++
  id = "a3f9c2"
  title = "Fix login bug"
  priority = 8
  status = "in_progress"
  ticket_type = "bug"
  dependencies = ["b7d41e"]
  +++
  Body text here.

Changes:
- display.rs: add DisplayFrontmatter struct, rewrite format_ticket using
  toml::to_string with id prepended as first frontmatter key
- tests.rs: update format_ticket_joins_dependencies and
  format_ticket_empty_dependencies for the new format
- integration.rs: update TestEnv::create to use --json for reliable
  ID extraction instead of parsing the key-value text format

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

nbd/src/display.rs

@@ -9,6 +9,8 @@
 
 use std::collections::HashSet;
 
+use serde::Serialize;
+
 use crate::graph::TicketGraph;
 use crate::store::MigrateReport;
 use crate::ticket::{Status, Ticket, TicketType};
@@ -23,15 +25,29 @@ const COL_PRI: usize = 5;
 const COL_TYPE: usize = 9;
 /// Width of the status column ("in_progress" = 11 chars, +2 padding).
 const COL_STATUS: usize = 13;
-/// Width of each label in the full ticket view ("Dependencies:" = 13 + 1 space).
+/// Width of each label in the diff view ("dependencies:" = 13 + 1 space).
 const LABEL_WIDTH: usize = 14;
 
 // ── Internal helpers ──────────────────────────────────────────────────────────
 
+/// Ticket metadata serialised into the TOML frontmatter block for display.
+///
+/// Mirrors the on-disk `MarkdownFrontmatter` in `store.rs` but adds `id` as
+/// the first field so that human-readable output is self-contained.
+#[derive(Serialize)]
+struct DisplayFrontmatter<'a> {
+    id: &'a str,
+    title: &'a str,
+    priority: u8,
+    status: &'a Status,
+    ticket_type: &'a TicketType,
+    dependencies: &'a [String],
+}
+
 /// Return the canonical display string for a [`Status`] variant.
 ///
 /// The strings match the serde serialisation: `"todo"`, `"in_progress"`,
-/// `"done"`.
+/// `"done"`, etc.
 fn status_str(status: &Status) -> &'static str {
     match status {
         Status::Todo => "todo",
@@ -58,37 +74,34 @@ fn ticket_type_str(ticket_type: &TicketType) -> &'static str {
 
 // ── Public formatting functions ───────────────────────────────────────────────
 
-/// Format a single ticket as a human-readable key–value table.
+/// Format a single ticket as a TOML-frontmatter markdown document.
 ///
-/// Each field is displayed on its own line with a label padded to
-/// [`LABEL_WIDTH`] characters.  An empty `Dependencies` field is rendered as
-/// an empty string rather than being omitted.
+/// The output mirrors the `.md` file format used on disk, with `id` added as
+/// the first frontmatter key so the output is self-contained. The ticket body
+/// follows the closing `+++` delimiter.
 ///
 /// ```text
-/// ID:           a3f9c2
-/// Title:        Fix login bug
-/// Body:         Users cannot log in with email addresses containing +
-/// Priority:     8
-/// Status:       in_progress
-/// Type:         bug
-/// Dependencies: b7d41e, c9e823
+/// +++
+/// id = "a3f9c2"
+/// title = "Fix login bug"
+/// priority = 8
+/// status = "in_progress"
+/// ticket_type = "bug"
+/// dependencies = ["b7d41e", "c9e823"]
+/// +++
+/// Users cannot log in with email addresses containing +
 /// ```
 pub fn format_ticket(ticket: &Ticket) -> String {
-    let deps = ticket.dependencies.join(", ");
-    [
-        format!("{:<LABEL_WIDTH$}{}", "ID:", ticket.id),
-        format!("{:<LABEL_WIDTH$}{}", "Title:", ticket.title),
-        format!("{:<LABEL_WIDTH$}{}", "Body:", ticket.body),
-        format!("{:<LABEL_WIDTH$}{}", "Priority:", ticket.priority),
-        format!("{:<LABEL_WIDTH$}{}", "Status:", status_str(&ticket.status)),
-        format!(
-            "{:<LABEL_WIDTH$}{}",
-            "Type:",
-            ticket_type_str(&ticket.ticket_type)
-        ),
-        format!("{:<LABEL_WIDTH$}{}", "Dependencies:", deps),
-    ]
-    .join("\n")
+    let fm = DisplayFrontmatter {
+        id: &ticket.id,
+        title: &ticket.title,
+        priority: ticket.priority,
+        status: &ticket.status,
+        ticket_type: &ticket.ticket_type,
+        dependencies: &ticket.dependencies,
+    };
+    let toml_str = toml::to_string(&fm).expect("frontmatter serialisation must not fail");
+    format!("+++\n{toml_str}+++\n{}", ticket.body)
 }
 
 /// Print a full tabular representation of a single ticket to stdout.

nbd/src/tests.rs

@@ -1387,25 +1387,30 @@ mod display {
         );
     }
 
-    /// `format_ticket` renders dependency IDs as a comma-separated list.
+    /// `format_ticket` renders dependency IDs as a TOML array.
     #[test]
     fn format_ticket_joins_dependencies() {
         let t = sample_ticket();
         let output = format_ticket(&t);
         assert!(
-            output.contains("b7d41e, c9e823"),
-            "dependencies should be comma-separated: {output}"
+            output.contains("b7d41e") && output.contains("c9e823"),
+            "dependencies should appear in frontmatter: {output}"
+        );
+        // TOML array format: dependencies = ["b7d41e", "c9e823"]
+        assert!(
+            output.contains("dependencies"),
+            "dependencies key should appear: {output}"
         );
     }
 
-    /// `format_ticket` renders an empty `Dependencies:` line when there are none.
+    /// `format_ticket` renders a `dependencies` key even when there are none.
     #[test]
     fn format_ticket_empty_dependencies() {
         let t = Ticket::new("aaaaaa".to_string(), "No deps".to_string());
         let output = format_ticket(&t);
         assert!(
-            output.contains("Dependencies:"),
-            "Dependencies label should always appear"
+            output.contains("dependencies"),
+            "dependencies key should always appear in frontmatter"
         );
     }
 

nbd/tests/integration.rs

@@ -42,11 +42,12 @@ impl TestEnv {
         self.run_from(&self.root, args)
     }
 
-    /// Run `nbd create` with the given extra arguments and return the printed
-    /// ticket ID extracted from stdout.
+    /// Run `nbd create --json` with the given extra arguments and return the
+    /// ticket ID extracted from JSON stdout.
     fn create(&self, extra_args: &[&str]) -> String {
         let mut args = vec!["create"];
         args.extend_from_slice(extra_args);
+        args.push("--json");
         let output = self.run(&args);
         assert!(
             output.status.success(),
@@ -54,11 +55,11 @@ impl TestEnv {
             String::from_utf8_lossy(&output.stderr)
         );
         let stdout = String::from_utf8(output.stdout).unwrap();
-        stdout
-            .lines()
-            .find(|l| l.trim_start().starts_with("ID:"))
-            .and_then(|l| l.split_whitespace().last())
-            .expect("could not extract ID from create output")
+        let parsed: serde_json::Value =
+            serde_json::from_str(&stdout).expect("create --json output should be valid JSON");
+        parsed["id"]
+            .as_str()
+            .expect("create --json output should have 'id' field")
             .to_string()
     }
 }