refactor: flatten skills/ and adopt Agent Plugins 1.0

The Agent Plugins standard reads only the immediate children of
skills/ and cannot be pointed elsewhere, so a bucketed tree is
invisible to every conformant client.

Rather than generate a flat copy of the repo into a package
directory — a builder, a validator, an allowlist, a drift CI job,
and every skill committed twice — remove the buckets.

- skills/ is flat and holds exactly the promoted 25
- in-progress/ -> drafts/, misc/ -> extras/, deprecated/ deleted
- new root plugin.json (Agent Plugins 1.0)
- .claude-plugin/plugin.json loses its 25-entry skills array
- docs/ keeps its category folders; it is now the only place a
  skill's category lives

Reasoning in .agents/adr/0003.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

scripts/link-skills.sh

@@ -5,7 +5,8 @@ set -euo pipefail
 # It is not a supported installer. Modifications to it — or requests for
 # modifications — will not be approved.
 #
-# Links all skills in the repository into the local skill directories used by
+# Links every skill in the repository — promoted (`skills/`) as well as
+# unpromoted (`drafts/`, `extras/`) — into the local skill directories used by
 # each agent harness:
 #   - ~/.claude/skills  — Claude Code
 #   - ~/.agents/skills  — Codex and other Agent Skills-compatible harnesses
@@ -22,7 +23,7 @@ while IFS= read -r -d '' skill_md; do
   src="$(dirname "$skill_md")"
   names+=("$(basename "$src")")
   srcs+=("$src")
-done < <(find "$REPO/skills" -name SKILL.md -not -path '*/node_modules/*' -not -path '*/deprecated/*' -print0)
+done < <(find "$REPO/skills" "$REPO/drafts" "$REPO/extras" -maxdepth 2 -name SKILL.md -not -path '*/node_modules/*' -print0)
 
 for DEST in "${DESTS[@]}"; do
   # If $DEST is a symlink that resolves into this repo, we'd end up writing the

scripts/sync-plugin-version.mjs

@@ -1,41 +1,55 @@
 #!/usr/bin/env node
-// Copies package.json's version into .claude-plugin/plugin.json.
+// Copies package.json's version into every plugin manifest:
+//   plugin.json                  — the Agent Plugins 1.0 manifest
+//   .claude-plugin/plugin.json   — the Claude Code manifest
 // Runs as part of `npm run version`, immediately after `changeset version`.
-// With --check it changes nothing and exits 1 if the two versions differ.
+// With --check it changes nothing and exits 1 if any version differs.
 
 import { readFileSync, writeFileSync } from "node:fs";
-import { dirname, join } from "node:path";
+import { dirname, join, relative } from "node:path";
 import { fileURLToPath } from "node:url";
 
 const repo = join(dirname(fileURLToPath(import.meta.url)), "..");
-const pluginPath = join(repo, ".claude-plugin", "plugin.json");
+const manifests = [
+  join(repo, "plugin.json"),
+  join(repo, ".claude-plugin", "plugin.json"),
+];
 
 const { version } = JSON.parse(readFileSync(join(repo, "package.json"), "utf8"));
-const source = readFileSync(pluginPath, "utf8");
-const plugin = JSON.parse(source);
+const check = process.argv.includes("--check");
+let failed = false;
 
-if (plugin.version === version) {
-  console.log(`plugin.json version is ${version} — already in sync`);
-  process.exit(0);
-}
+for (const path of manifests) {
+  const name = relative(repo, path);
+  const source = readFileSync(path, "utf8");
+  const manifest = JSON.parse(source);
 
-if (process.argv.includes("--check")) {
-  console.error(
-    `plugin.json version is ${plugin.version}, package.json is ${version}. Run \`node scripts/sync-plugin-version.mjs\`.`,
+  if (manifest.version === version) {
+    console.log(`${name} version is ${version} — already in sync`);
+    continue;
+  }
+
+  if (check) {
+    console.error(
+      `${name} version is ${manifest.version}, package.json is ${version}. Run \`node scripts/sync-plugin-version.mjs\`.`,
+    );
+    failed = true;
+    continue;
+  }
+
+  // Rewrite only the version line, to keep the key order and the formatting.
+  const updated = source.replace(
+    /("version"\s*:\s*")[^"]*(")/,
+    `$1${version}$2`,
   );
-  process.exit(1);
+
+  if (JSON.parse(updated).version !== version) {
+    console.error(`Could not find a version field to replace in ${path}.`);
+    process.exit(1);
+  }
+
+  writeFileSync(path, updated);
+  console.log(`${name} version ${manifest.version} -> ${version}`);
 }
 
-// Rewrite only the version line, to keep the key order and the formatting.
-const updated = source.replace(
-  /("version"\s*:\s*")[^"]*(")/,
-  `$1${version}$2`,
-);
-
-if (JSON.parse(updated).version !== version) {
-  console.error(`Could not find a version field to replace in ${pluginPath}.`);
-  process.exit(1);
-}
-
-writeFileSync(pluginPath, updated);
-console.log(`plugin.json version ${plugin.version} -> ${version}`);
+process.exit(failed ? 1 : 0);