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/git/skills/git-remotes/references/sources.md

@@ -0,0 +1,71 @@
+---
+# Research sources referenced by this skill
+# Each entry documents where the skill's guidance came from.
+---
+
+## git-scm-remote-docs
+
+**Description:** Git SCM official documentation for `git remote` command — remote configuration, add/remove/rename, URL management, inspection, and housekeeping.
+
+**Source:** https://git-scm.com/docs/git-remote
+
+- **Research doc:** plugins/git/docs/research/docs/git/remotes.md → `## Remote Management (`git remote`)`
+
+**Contributing files:**
+- SKILL.md (Remote Management section)
+- references/remotes.md (`set-url` full form)
+
+---
+
+## git-scm-fetch-docs
+
+**Description:** Git SCM official documentation for `git fetch` command — fetching from remotes, tracking branch updates, pruning stale refs, shallow clones, and refspecs.
+
+**Source:** https://git-scm.com/docs/git-fetch
+
+- **Research doc:** plugins/git/docs/research/docs/git/remotes.md → `## Fetching (`git fetch`)`
+
+**Contributing files:**
+- SKILL.md (Fetch Operations section, Gotchas)
+- references/remotes.md (shallow clones, default fetch refspec)
+
+---
+
+## git-scm-push-docs
+
+**Description:** Git SCM official documentation for `git push` command — pushing branches, tags, force-push safety (--force-with-lease, --force-if-includes), refspecs, and multi-remote workflows.
+
+**Source:** https://git-scm.com/docs/git-push
+
+- **Research doc:** plugins/git/docs/research/docs/git/remotes.md → `## Pushing (`git push`)`
+
+**Contributing files:**
+- SKILL.md (Push Operations section, Gotchas)
+- references/remotes.md (force-push safety full detail, server-side deny policies)
+
+---
+
+## git-scm-pull-docs
+
+**Description:** Git SCM official documentation for `git pull` command — fetch + merge/rebase strategies, divergence resolution (--ff-only, --rebase, merge), config precedence, and pull-specific gotchas.
+
+**Source:** https://git-scm.com/docs/git-pull
+
+- **Research doc:** plugins/git/docs/research/docs/git/remotes.md → `## Pulling (`git pull`)`
+
+**Contributing files:**
+- SKILL.md (Pull Operations section, Gotchas)
+- references/remotes.md (pull config precedence)
+
+---
+
+## context7-git-htmldocs
+
+**Description:** Context7 MCP library providing current Git documentation and API reference — used for validation of modern Git syntax, behavior, and config semantics. This is a blanket cross-cutting reference and does not map to a single heading in the research doc; it informed terminology and syntax checks across all sections.
+
+**Source:** Context7 MCP / Git library
+
+- **Research doc:** plugins/git/docs/research/docs/git/remotes.md (cross-cutting — no dedicated section)
+
+**Contributing files:**
+- SKILL.md (all sections)