Remove VuePress; publish docs as plain Markdown (#561)

Drop the VuePress toolchain and doc-site publish pipeline so docs are plain Markdown browsable on GitHub.

- Delete VuePress config, npm tooling, deploy scripts, and docs .gitignore

- Delete deploy-document.yml GitHub Actions workflow (built/pushed gh-pages)

- Add docs/README.md index and a Documentation contents ToC to EN/JA READMEs

- Update AGENTS.md, dev-docs, and development-workflow skill to describe plain Markdown docs

- Add ADR 0005 recording the decision

Co-authored-by: Kazuki Ota <117221407+kaota_microsoft@users.noreply.github.com>
Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>

Author: 3 people

.agents/skills/development-workflow/SKILL.md

@@ -1,6 +1,6 @@
 ---
 name: development-workflow
-description: ReactiveProperty repository development policy. Use whenever you implement a feature or bug fix, change library or test code under Source/ or Test/, make a design or architecture decision, or write documentation in this repo. Enforces strict Test-Driven Development (Red -> Green -> Refactor) with MSTest and `dotnet test ReactiveProperty.slnx`, requires recording design decisions as ADRs under dev-docs/adr/, and defines the documentation split: docs/ is user-facing (published via VuePress) while dev-docs/ holds implementer/contributor documentation. Triggers include "implement", "add feature", "fix bug", "TDD", "red green refactor", "design decision", "architecture", "ADR", "where do docs go", and "contributor docs".
+description: ReactiveProperty repository development policy. Use whenever you implement a feature or bug fix, change library or test code under Source/ or Test/, make a design or architecture decision, or write documentation in this repo. Enforces strict Test-Driven Development (Red -> Green -> Refactor) with MSTest and `dotnet test ReactiveProperty.slnx`, requires recording design decisions as ADRs under dev-docs/adr/, and defines the documentation split: docs/ is user-facing (plain Markdown browsed on GitHub) while dev-docs/ holds implementer/contributor documentation. Triggers include "implement", "add feature", "fix bug", "TDD", "red green refactor", "design decision", "architecture", "ADR", "where do docs go", and "contributor docs".
 ---
 # Development Workflow (ReactiveProperty)
 
@@ -84,9 +84,9 @@ Trivial, reversible choices (local refactors, naming) do **not** need an ADR.
 
 ## 3. Documentation split: `docs/` vs `dev-docs/`
 
-- **`docs/` = user-facing** documentation, published as the VuePress site
-  (`npm run docs:build`). Write here for library *consumers*: getting-started, API usage,
-  samples. Available in English and Japanese (`*-ja`).
+- **`docs/` = user-facing** documentation, plain Markdown browsed directly on GitHub (no site
+  generator). Write here for library *consumers*: getting-started, API usage,
+  samples. Available in English and Japanese (`*-ja`). Keep links relative (`.md`).
 - **`dev-docs/` = implementer/contributor-facing** documentation, **not** published.
   Write here for people working *on* ReactiveProperty: architecture notes, internal design,
   contributor workflow, and ADRs (`dev-docs/adr/`).

.github/workflows/deploy-document.yml

@@ -37,7 +37,7 @@ Test/                           Unit tests (MSTest)
   ReactiveProperty.WPF.ManualTests/    Manual/interactive WPF test app
 Samples/                        Example apps (WPF, Blazor, MAUI-style, Prism, etc.)
 Benchmark/                      BenchmarkDotNet projects (separate solution)
-docs/                           VuePress documentation site (user-facing, published)
+docs/                           Plain-Markdown documentation (user-facing; browse on GitHub)
 dev-docs/                       Implementer/contributor docs + ADRs (not published)
 skills/                         Published agent skills for ReactiveProperty *users* (consumers)
 .agents/skills/                 Agent skills for working *on* this repo (contributors)
@@ -116,13 +116,9 @@ See the **`development-workflow`** skill (`.agents/skills/development-workflow/S
 - Add tests under the matching `Test/*` project; mirror the namespace `ReactiveProperty.Tests`.
 
 ## Documentation
-- **`docs/` = user-facing**, built with **VuePress** (English + Japanese `*-ja` variants):
-  ```pwsh
-  cd docs
-  npm install
-  npm run docs:dev     # local dev server
-  npm run docs:build   # static build
-  ```
+- **`docs/` = user-facing**, plain Markdown (English + Japanese `*-ja` variants). There is no
+  site generator — just browse the folder on GitHub. Keep links relative (`.md`) so they work
+  both on GitHub and in local editors.
 - **`dev-docs/` = implementer/contributor-facing** (not published): architecture notes,
   contributor workflow, and ADRs in `dev-docs/adr/`. See `dev-docs/README.md`.
 

AGENTS.md

@@ -5,7 +5,7 @@ This folder holds documentation for people working **on** ReactiveProperty
 
 | Folder | Audience | Published? |
 |--------|----------|------------|
-| [`../docs/`](../docs) | Library **users** (consumers) | Yes — built and published with VuePress |
+| [`../docs/`](../docs) | Library **users** (consumers) | Plain Markdown, browsable on GitHub |
 | `dev-docs/` (this folder) | **Implementers / contributors** | No |
 
 Put "how does a consumer use this feature?" content in `docs/`. Put "how/why is this

dev-docs/README.md

@@ -0,0 +1,60 @@
+# 0005. Remove VuePress; publish docs as plain Markdown on GitHub
+
+- **Status:** Accepted
+- **Date:** 2026-07-05
+- **Deciders:** ReactiveProperty maintainers
+
+## Context
+
+The user-facing documentation under `docs/` was built with [VuePress](https://vuepress.vuejs.org/)
+1.5 and published to GitHub Pages (the `gh-pages` branch) by the
+`.github/workflows/deploy-document.yml` workflow. This added a Node.js/npm toolchain
+(`docs/package.json`, `docs/package-lock.json`), VuePress-specific configuration
+(`docs/docs/.vuepress/config.js`), deploy scripts (`docs/deploy.ps1`, `docs/deploy.sh`), and a
+CI job whose only purpose was to build and push the static site.
+
+The documentation content is already ordinary Markdown with relative `.md` links and relative
+image paths, so it renders correctly when browsed directly on GitHub. The VuePress layer mainly
+provided a navigation sidebar and theming — nice-to-have, but not essential for a project that is
+in maintenance/active-support mode and whose author recommends the successor library
+[R3](https://github.com/Cysharp/R3) for new apps. Maintaining the Node toolchain and a bespoke
+publish pipeline is ongoing overhead disproportionate to that value.
+
+## Decision
+
+We will remove the VuePress dependency and treat `docs/` as plain Markdown that is read by
+browsing the folder on GitHub.
+
+Concretely:
+
+1. Delete the VuePress configuration and Node tooling: `docs/docs/.vuepress/config.js`,
+   `docs/package.json`, `docs/package-lock.json`, `docs/deploy.ps1`, `docs/deploy.sh`, and the
+   VuePress-only `docs/.gitignore`.
+2. Delete the `deploy-document.yml` GitHub Actions workflow that built and pushed the site.
+3. Preserve navigation for GitHub readers by adding a top-level `docs/README.md` index and a
+   "Documentation contents" table of contents to `docs/docs/README.md` and
+   `docs/docs-ja/README.md` (mirroring the old sidebar).
+4. Update contributor docs (`AGENTS.md`, `dev-docs/README.md`, and the `development-workflow`
+   skill) to describe `docs/` as plain Markdown rather than a published VuePress site.
+
+Disabling GitHub Pages itself and deleting the `gh-pages` branch are repository settings that
+cannot be changed from repository files; they are a manual follow-up for a maintainer.
+
+### Alternatives considered
+
+- **Keep VuePress** — rejected: ongoing Node/npm maintenance and a bespoke publish pipeline for
+  marginal benefit on a maintenance-mode project.
+- **Migrate to another static-site generator (DocFX, MkDocs, Docusaurus, VitePress)** — rejected:
+  still introduces a toolchain and publish pipeline; the stated goal is to remove the site build
+  entirely and rely on GitHub's Markdown rendering.
+
+## Consequences
+
+- No Node.js/npm toolchain or site-build step is required to work on the docs; edits are just
+  Markdown.
+- The hosted documentation site (GitHub Pages) will no longer be updated and should be disabled
+  by a maintainer; existing deep links to the old site will break. Links from the repo now point
+  at the Markdown files in `docs/`.
+- Navigation is provided by README indexes rather than a generated sidebar; contributors must keep
+  those indexes in sync when adding or renaming pages.
+- Documentation links must stay relative (`.md`) so they resolve both on GitHub and locally.

dev-docs/adr/0005-remove-vuepress-plain-markdown-docs.md

@@ -38,3 +38,4 @@ Trivial, easily reversible choices (local refactors, naming) do not need an ADR.
 | [0002](./0002-reactivetimer-fixed-period-interval.md) | ReactiveTimer uses a fixed-period ITimer; Interval changes take effect on next Start | Accepted |
 | [0003](./0003-reactiveproperty-r3-migration-bridge.md) | Ship a permanent minimal `ReactiveProperty.R3` migration bridge and a migration skill | Accepted |
 | [0004](./0004-reactiveproperty-r3-wpf-event-to-reactive.md) | Provide R3-targeting EventToReactive trigger actions in a new ReactiveProperty.R3.WPF package | Accepted |
+| [0005](./0005-remove-vuepress-plain-markdown-docs.md) | Remove VuePress; publish docs as plain Markdown on GitHub | Accepted |

dev-docs/adr/README.md

@@ -0,0 +1,10 @@
+# ReactiveProperty documentation
+
+These docs are plain Markdown — just browse them here on GitHub.
+
+- **English:** [`docs/`](./docs/README.md)
+- **日本語:** [`docs-ja/`](./docs-ja/README.md)
+
+> For brand-new apps the author recommends the successor library
+> [R3](https://github.com/Cysharp/R3). See the
+> [Migrate to R3](./docs/advanced/r3-migration.md) guide.