chore: scaffold @haylan/opencode-pocock package

NOTICE

@@ -0,0 +1,17 @@
+This package vendors and redistributes third-party material:
+
+- skills/ (except agents/*.md system prompts written for this package) is a verbatim snapshot of
+  the skills from Matt Pocock's "skills" repository (https://github.com/mattpocock/skills),
+  Copyright (c) Matt Pocock, licensed under the MIT License. The upstream revision is recorded in
+  upstream/UPSTREAM.json and .opencode/state/upstream.json. All engineering discipline in the
+  skills is Matt Pocock's work.
+
+- The `pr` skill incorporates material from Dex Horthy's "show-me" skill
+  (https://github.com/humanlayer/skills), attributed in the skill's frontmatter
+  (metadata.credits) and CREDITS.md, preserved verbatim.
+
+- The orchestrator/worker agent design is adapted from mcdays94/pocock-agents
+  (https://github.com/mcdays94/pocock-agents), Copyright (c) mcdays94, MIT License.
+
+- The Gitea npm registry release scripts are adapted from haylan/fastcrw-opencode-websearch,
+  Apache-2.0.