docs: add mdBook docs-site, publish workflow, and release-notes tooling

Add a docs-site (mdBook) with a Gitea publish-docs workflow, a
release-notes generator script (release:notes) that turns a commit
range's TRACES into grouped notes, the background-audio feature spec,
and CLAUDE.md. Ignore docs-site build artifacts.

scripts/release-notes.ts

@@ -0,0 +1,137 @@
+#!/usr/bin/env bun
+/**
+ * release-notes.ts — turn a commit range into capability-level release notes
+ * using the TRACES graph instead of raw commit subjects.
+ *
+ * Usage:
+ *   bun run scripts/release-notes.ts [<range>]
+ *   bun run scripts/release-notes.ts v0.0.15..HEAD
+ *
+ * With no argument it uses <latest tag>..HEAD (or the whole history if untagged).
+ *
+ * How it works:
+ *   1. `git diff --name-only <range>` → files the range changed.
+ *   2. Read each changed file's `TRACES:` comments → requirement IDs.
+ *   3. Resolve IDs to descriptions from docs/requirements.md.
+ *   4. Group: UR → Features, DR/IR → Improvements. Deduped, so many commits
+ *      touching one requirement collapse to one line.
+ *
+ * This is a drafting aid for docs/release-checklist.md — review the output,
+ * it does not invent descriptions for untraced changes (those are listed
+ * separately so nothing is silently dropped).
+ */
+
+import { execSync } from "node:child_process";
+import { readFileSync, existsSync } from "node:fs";
+
+const TRACE_RE = /TRACES:\s*([^\n*]+)/g;
+const ID_RE = /\b(UR|IR|DR|JA|UT|IT)-\d+\b/g;
+const REQ_ROW_RE = /^\|\s*((?:UR|IR|DR|JA)-\d+)\s*\|\s*([^|]+?)\s*\|/;
+
+function sh(cmd: string): string {
+  return execSync(cmd, { encoding: "utf8" }).trim();
+}
+
+function defaultRange(): string {
+  try {
+    const tag = sh("git describe --tags --abbrev=0");
+    return `${tag}..HEAD`;
+  } catch {
+    return ""; // no tags: fall through to whole-history diff
+  }
+}
+
+/** Map requirement ID → human description, parsed from docs/requirements.md. */
+function loadRequirementDescriptions(): Map<string, string> {
+  const map = new Map<string, string>();
+  const text = readFileSync("docs/requirements.md", "utf8");
+  for (const line of text.split("\n")) {
+    const m = line.match(REQ_ROW_RE);
+    // First definition wins: the descriptive tables come before the later
+    // cross-reference tables, whose cells hold linked IDs (or "-"), not prose.
+    if (m && !map.has(m[1])) map.set(m[1], m[2].trim());
+  }
+  return map;
+}
+
+function changedFiles(range: string): string[] {
+  const cmd = range
+    ? `git diff --name-only ${range}`
+    : "git ls-files"; // untagged repo: describe everything currently traced
+  return sh(cmd)
+    .split("\n")
+    .filter((f) => f && existsSync(f));
+}
+
+/** Collect requirement IDs referenced by TRACES comments in the given files. */
+function idsFromFiles(files: string[]): Set<string> {
+  const ids = new Set<string>();
+  for (const file of files) {
+    let content: string;
+    try {
+      content = readFileSync(file, "utf8");
+    } catch {
+      continue;
+    }
+    for (const trace of content.matchAll(TRACE_RE)) {
+      for (const id of trace[1].matchAll(ID_RE)) ids.add(id[0]);
+    }
+  }
+  return ids;
+}
+
+function main() {
+  const range = process.argv[2] ?? defaultRange();
+  const descriptions = loadRequirementDescriptions();
+  const files = changedFiles(range);
+  const ids = idsFromFiles(files);
+
+  const features: string[] = []; // UR
+  const improvements: string[] = []; // DR / IR
+  const unknown: string[] = []; // traced but not in requirements.md
+
+  for (const id of [...ids].sort()) {
+    const desc = descriptions.get(id);
+    if (id.startsWith("UT") || id.startsWith("IT")) continue; // tests aren't notes
+    if (!desc) {
+      if (!id.startsWith("UT") && !id.startsWith("IT")) unknown.push(id);
+      continue;
+    }
+    const line = `- ${desc} (${id})`;
+    if (id.startsWith("UR")) features.push(line);
+    else improvements.push(line);
+  }
+
+  const header = range || "(entire history — no tags found)";
+  const out: string[] = [`## Release notes — ${header}`, ""];
+
+  if (features.length) out.push("### ✨ Features", ...features, "");
+  if (improvements.length) out.push("### 🚀 Improvements", ...improvements, "");
+  if (unknown.length)
+    out.push(
+      "### ⚠️ Traced IDs missing from requirements.md",
+      ...unknown.map((id) => `- ${id}`),
+      "",
+    );
+
+  const untraced = files.filter((f) => {
+    try {
+      return !/TRACES:/.test(readFileSync(f, "utf8"));
+    } catch {
+      return false;
+    }
+  });
+  if (untraced.length)
+    out.push(
+      `### 📝 Changed files without TRACES (${untraced.length}) — review manually`,
+      ...untraced.map((f) => `- ${f}`),
+      "",
+    );
+
+  if (!features.length && !improvements.length)
+    out.push("_No traced requirements in this range._", "");
+
+  console.log(out.join("\n"));
+}
+
+main();