Add explicit patch.moi harness submodules

.gitmodules

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+[submodule "harness/upstream"]
+	path = harness/upstream
+	url = https://github.com/peezy-tech/patch-moi-harness.git
+	branch = main
+[submodule "harness/fork"]
+	path = harness/fork
+	url = https://github.com/matamune-peezy/patch-moi-harness.git
+	branch = main

harness/README.md

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+# patch.moi Harnesses
+
+This directory holds small, real repositories used to exercise patch.moi
+against upstream/fork maintenance flows.
+
+## Layout
+
+- `upstream`: the public upstream GitHub repository.
+- `fork`: a local maintained fork, cloned from a real GitHub fork.
+
+The upstream repository is:
+
+```text
+https://github.com/peezy-tech/patch-moi-harness.git
+```
+
+The fork repository is:
+
+```text
+https://github.com/matamune-peezy/patch-moi-harness.git
+```
+
+The fork should also know about the upstream and jojo remotes:
+
+```bash
+git -C harness/fork remote get-url upstream >/dev/null 2>&1 || \
+  git -C harness/fork remote add upstream https://github.com/peezy-tech/patch-moi-harness.git
+git -C harness/fork remote get-url jojo >/dev/null 2>&1 || \
+  git -C harness/fork remote add jojo git@jojo.build:peezy-tech/patch-moi-harness.git
+git -C harness/fork fetch upstream
+git -C harness/fork fetch jojo
+```
+
+## Branch Model
+
+- `harness/upstream` `main`: upstream package history and upstream releases.
+- `harness/fork` `upstream/main`: fetched copy of upstream `main`.
+- `harness/fork` `main`: maintained fork with patch commits applied.
+- `harness/fork` `jojo/main`: service-style maintained fork remote.
+
+The upstream npm package is `@peezy.tech/patch-moi-harness`. It publishes from
+GitHub tags named `v*` through the `npm-publish` GitHub environment.
+
+The fork npm package is `@peezy.tech/patch-moi-harness-fork`. It is configured
+to publish from GitHub fork tags named `fork-v*` through the same
+`npm-publish` environment, once the npm trusted publisher exists for the fork
+package.
+
+## Scenario: Upstream Release
+
+Use this when you want to simulate upstream changing and publishing a new
+release.
+
+```bash
+cd harness/upstream
+npm version patch --no-git-tag-version
+npm test
+git add package.json package-lock.json
+git commit -m "Release 0.1.4"
+git tag v0.1.4
+git push origin main v0.1.4
+```
+
+Expected result: GitHub Actions publishes the upstream package to npm with
+trusted publishing.
+
+## Scenario: Fork Feature Patch
+
+Use this when you want to simulate local feature development on top of
+upstream.
+
+```bash
+cd harness/fork
+git fetch upstream
+git checkout main
+npm test
+# edit source files
+git add .
+git commit -m "Add local fork feature"
+git push origin main
+git push jojo main
+```
+
+Expected result: the GitHub fork and jojo maintained branch both move ahead of
+the last upstream commit.
+
+## Scenario: Rebase Fork Onto Upstream
+
+Use this when upstream has released and the maintained fork needs to carry its
+patches forward.
+
+```bash
+cd harness/fork
+git fetch upstream
+git fetch origin
+git checkout main
+git rebase upstream/main
+npm test
+git push --force-with-lease origin main
+git push --force-with-lease jojo main
+```
+
+Expected result: fork `main` is still patched, but its base is the latest
+upstream release.
+
+## Scenario: Fork Release
+
+Use this when the maintained fork should do its own release cycle.
+
+```bash
+cd harness/fork
+npm version prerelease --preid fork --no-git-tag-version
+npm test
+git add package.json package-lock.json
+git commit -m "Release fork package"
+version=$(node -p "require('./package.json').version")
+git tag "fork-v${version}"
+git push origin main "fork-v${version}"
+git push jojo main
+```
+
+Expected result: GitHub Actions in the fork publishes
+`@peezy.tech/patch-moi-harness-fork`, provided npm has a trusted publisher for
+`matamune-peezy/patch-moi-harness`, workflow `publish.yml`, environment
+`npm-publish`.
+
+## Scenario: Remote-Only Service
+
+Use this when testing patch.moi service behavior without relying on local
+working trees.
+
+```text
+upstream repo: https://github.com/peezy-tech/patch-moi-harness.git
+upstream branch: main
+fork repo: https://github.com/matamune-peezy/patch-moi-harness.git
+fork branch: main
+service mirror: git@jojo.build:peezy-tech/patch-moi-harness.git
+service branch: main
+```
+
+Expected result: patch.moi can reason from remote refs alone, then create a
+workspace only when it needs to apply or validate the patch stack.

harness/fork

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+Subproject commit 9fd9d8c31a004059e16f769453d75afba29959be

harness/upstream

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+Subproject commit 772bdd62c6031302b57b175e428110fa51671861