feat(onedev): redistribute TOD's agent skills through a plugin wrapper

OneDev ships TOD, an official CLI, and eight SKILL.md files alongside it. apm installs raw
SKILL.md sources straight from a git repo, so those skills need no reauthoring — but a
`marketplace.packages` entry takes a local `source:` path, so a third-party repo cannot be
listed for redistribution on its own.

plugins/onedev is that wrapper. It carries no primitives yet: it pins
code.onedev.io/onedev/tod#v4.3.4 so consumers installing `onedev` from the holocron
marketplace pick up TOD's eight skills transitively, and it is where this repo's own OneDev
skills and orchestrator agent will live once there is a gap worth filling.

The pin is deliberate. The six first-party dependencies stay unpinned for default-branch
parity because they are this repo's own content; tracking a third-party project's main
would import an outside project's drift instead.

Impact: root apm.yml consumes the wrapper by git+path, so `apm install` does not resolve
until this is on the remote's main — including the copy kyberforge's SessionStart hook runs
on launch. Accepted deliberately; this merges immediately. Gitea remains the tracker of
record and ADR-0007 is untouched.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01NwD8Egs5r4ndqeFLmhusX2

.claude-plugin/marketplace.json

@@ -36,6 +36,13 @@
       "category": "Version Control",
       "source": "./plugins/gitea"
     },
+    {
+      "name": "onedev",
+      "description": "Skills and agents for working with a OneDev forge through the TOD CLI — the forge's own objects, as distinct from the local git clone.",
+      "version": "0.1.0",
+      "category": "Version Control",
+      "source": "./plugins/onedev"
+    },
     {
       "name": "core",
       "description": "Skills for authoring and auditing a repo's AGENTS.md and the provider adapter files that defer to it.",