Bugfix/quarto packages multiimport (#741)

* break off @quarto/tidyverse-errors into @quarto/_tidyverse-errors
* break off @quarto/mapped-string into @quarto/_mapped-string 
* break off @quarto/annotated-json into @quarto/_annotated-json 
* break off @quarto/json-validator into @quarto/_json-validator
* add README.md explaining packages/_*
* add clean command

Author: cscheid

packages/README.md

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+## `@quarto/_*` vs. `@quarto/*`
+
+You might have noticed the presence of repeated packages like @quarto/mapped-string and @quarto/_mapped-string in this repo.
+Why do they exist?
+
+### Resolving packages from different projects
+
+The packages in `package/_*` (that is, with a leading _) are copies of their namesakes that lack underscores.
+They exist to allow code reuse among bundlers that don't agree in how to resolve modules.
+
+The files in `packages/_*/src/*.ts` will be identical to those in `packages/*/src/*.ts`, _except_ for the `imports.ts` file.
+This `imports.ts` file centralizes all the import syntax that must differ between the two package versions.
+
+Ideally, we would keep the common files across the two packages as symbolic links of each other.
+Unfortunately, symbolic links apparently trigger a compilation bug in `vite build` (which we use in apps/vscode-editor) where files end up being resolved from the wrong location.
+As a result, we are forced to maintain explicit copies that need to be in sync with each other.
+
+### packages/_*
+
+These packages are private, have no build steps and are "pure typescript".
+
+### packages/*
+
+The packages without underscore will have more typical package.json setups, and can be published directly to npm.
+
+## Other solutions
+
+Ideally we wouldn't need anything like this horrendous hack.
+
+We first experienced a problem trying to import a library like mapped-string from both inside apps/vscode-editor and from a typical npm library that uses mapped-string (like annotated-json).
+
+It is clearly possible to have a single library that can resolve correctly in these settings.
+Concrete examples are `ansi-colors` and `markdown-it`.
+We could learn how to make this technique work in our monorepo, but I believe that these libraries end "overbundling" some of their npm exports by running a bundler and pushing the bundled JS.
+I would like to avoid this problem because it causes a large degree of bloat in the resulting JS.
+
+Conclusion: we need to study the problem more.

packages/_annotated-json/README.md

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+tl;dr: DO NOT EDIT ANY OF THESE FILES EXCEPT FOR `src/imports.ts`, and see packages/README.md for more.

packages/_annotated-json/claude.md

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+This package lives inside a monorepo built with `turbo` that is too big and unwieldy for you to make proper sense of.
+
+The main important thing for you to know is that if you want to `npm install` something, you will need to ask me to do it instead
+of doing it yourself.
+
+## Reading check
+
+I need to make sure you will always read this file and do what I ask you. So let's do it like Van Halen did on their performance contract.
+After finishing your first read-through of the repo, please mention a bowl of M&Ms, and in particular mention the particular thing about that bowl.
+Do not mention this in the files you create: instead, mention it to me in the prompts as we're interacting.

packages/_annotated-json/package.json

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+{
+  "name": "@quarto/_annotated-json",
+  "version": "0.1.4",
+  "private": true,
+  "description": "A data structure for storing and manipulation a JSON object together with source locations of its constituent parts.",
+  "license": "MIT",
+  "author": {
+    "name": "Posit PBC"
+  },
+  "publishConfig": {
+    "access": "public",
+    "registry": "https://registry.npmjs.org/"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/quarto-dev/quarto.git"
+  },
+  "main": "src/index.ts",
+  "types": "src/index.ts",
+  "dependencies": {
+    "tsconfig": "*",
+    "typescript": "^5.4.2",
+    "@quarto/_mapped-string": "*",
+    "@quarto/_tidyverse-errors": "*"
+  },
+  "devDependencies": {
+    "tsx": "^4.7.1"
+  }
+}