feat(git-plugin): add complete git workflow automation suite

## Why
The git plugin only covered a partial slice of common git workflows.
This adds the remaining skill set (branches, commits, history, remotes,
submodules, workflow, worktrees) plus a git-orchestrate agent so the
plugin can handle end-to-end git automation instead of a handful of
commands.

## Implementation Notes
Each new skill was validated against its research docs and org
conventions after initial authoring, which surfaced hallucinated
version pins, factual errors, and completeness gaps that were
corrected in the same pass rather than left for follow-up.

## Impact
Bumps the git plugin to 1.3.0.

Co-authored-by: Claude Sonnet 5 <noreply@anthropic.com>

plugins/kyberforge/skills/skill-author/SKILL.md

@@ -103,6 +103,8 @@ metadata:
     - another-slug
 ```
 
+**Embedding org-specific policy** — if a skill encodes a rule sourced from an org convention file (e.g. `core/instructions/*.md`), inline that content directly into the skill (SKILL.md or a `references/` file) rather than pointing to the file's path. Plugins must be self-contained and portable — the org file may not exist wherever the plugin is installed, and in this repo such files are meant to be deleted once their content is fully embedded downstream. Tag the inlined content with a `source_keys` entry using the same `references/sources.md` schema as Step 5, noting in the `Research doc:` field that the source is an org convention rather than a plugin research corpus entry, so provenance survives after the source file is gone.
+
 **Body — include only what the agent lacks**
 
 Rename the placeholder section heading to one that fits the skill's structure — `## Step 1`, `## Workflow`, `## Instructions`, etc.