feat: implement v0

[ho991217]

No description provided.

[Copilot]

Pull request overview

This PR transitions the project from an Nx-based monorepo to a single-package CLI (“pull-up”) and introduces an initial (“v0”) rule/transform engine plus a CODEOWNERS aggregation rule.

Changes:

• Replace Nx workspace setup with a single-package build using tsdown.
• Add a new core rules API (Rule, resolveRule, defineRule) and a CODEOWNERS rule implementation.
• Add a Clipanion-based CLI with check and sync commands.

Reviewed changes

Copilot reviewed 22 out of 25 changed files in this pull request and generated 10 comments.

Show a summary per file

File	Description
yarn.lock	Updates dependency lockfile for the new single-package setup and CLI deps.
tsdown.config.ts	Adds tsdown build config for the CLI entrypoint/bundle settings.
tsconfig.json	Updates TS project include list to cover the new tsdown config file.
src/core/types.ts	Introduces core types (Rule, Ruleset, snapshots, context).
src/core/rules/index.ts	Exports built-in rules.
src/core/rules/codeowners-rule.ts	Adds CODEOWNERS aggregation rule and marker-section writing.
src/core/resolve-rule.ts	Implements globbing + reading inputs + invoking rule transforms.
src/core/index.ts	Public barrel export for the core package surface.
src/core/define-rule.ts	Adds a small helper for defining rules.
src/cli/utils.ts	Adds repository root discovery utility.
src/cli/index.ts	Adds Clipanion CLI entrypoint + command registration.
src/cli/constants.ts	Defines default rules exposed by the CLI.
src/cli/commands/sync.ts	Implements pullup sync command to write generated outputs.
src/cli/commands/index.ts	CLI command barrel export.
src/cli/commands/check.ts	Implements pullup check command to validate outputs are up to date.
packages/core/tsdown.config.ts	Removes old packages/core build config.
packages/core/tsconfig.json	Removes old packages/core TS config.
packages/core/src/index.ts	Removes placeholder core package source.
packages/core/package.json	Removes old core package manifest.
package.json	Converts project to a distributable CLI package and adds deps/scripts.
nx.json	Removes Nx workspace configuration.
eslint.config.mjs	Updates ESLint TS project references for the new structure.
README.md	Updates project name/description text.
.vscode/settings.json	Removes some editor save-time code actions.
.gitignore	Removes Nx cache ignores; keeps dist ignore.

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