chore(lint): replace markdownlint with rumdl

Author: kvokka

.devcontainer/devcontainer.json

@@ -43,7 +43,6 @@
 				"ms-azuretools.vscode-docker",
 				"nefrob.vscode-just-syntax",
 				"redhat.vscode-yaml",
-				"DavidAnson.vscode-markdownlint",
 				"Nuxt.mdc",
 				"shd101wyy.markdown-preview-enhanced",
 				"github.vscode-github-actions",

.markdownlint-cli2.yaml

@@ -0,0 +1,3 @@
+[global]
+exclude = ["AGENTS.md", "GEMINI.md", "CHANGELOG.md", "prompts/", "docs/**/*"]
+disable = ["MD013", "MD033"]

.rumdl.toml

@@ -14,6 +14,7 @@ A universal boilerplate for reliable, isolated, and AI-friendly development, inc
 1. [just](https://github.com/casey/just): Simple command runner.
 2. [prek](https://github.com/j178/prek): Pre-commit runner (intial set via [dotfiles](https://github.com/kvokka/dotfiles/))
 3. [aicommit2](https://github.com/tak-bro/aicommit2): Git message generator
+4. [rumdl](https://github.com/rvben/rumdl): Markdown linter
 
 ## Directory Structure
 
@@ -58,10 +59,10 @@ different projects AND for MCP's use `~./.devcontainer/.env.devcontainer`.
 #### Loading order
 
 - `containerEnv` section of the
-[`devcontainer.json`](./.devcontainer/devcontainer.json)  with build env vars.
+[`devcontainer.json`](./.devcontainer/devcontainer.json) with build env vars.
 
 - `remoteEnv` section of the
-[`devcontainer.json`](./.devcontainer/devcontainer.json)  with runtime env vars.
+[`devcontainer.json`](./.devcontainer/devcontainer.json) with runtime env vars.
 
 - *[optional]* global env file on the host machine in `~/.devcontainer/.env.devcontainer` file