refactor(code-editor): update to Codemirror 6

[e111077]

Upgrade to codemirror 6

per-file summary

src/playground-code-editor.ts

Major rewrite to adapt to CodeMirror 6:

• Replaced CodeMirror 5 imports and types with CodeMirror 6 equivalents (EditorState, EditorView, Extension, Compartment, etc.).
• Removed the old playgroundStyles import and added the new styles import from playground-styles.ts.
• Applied the .tok-* classes with syntaxHighlighting(classHighlighter, {fallback: true})
• Changed internal state management from CM5's Editor instance to CM6's EditorView and EditorState.
• Updated property getters (cursorPosition, cursorIndex, tokenUnderCursor) to use the CM6 API.
• Rewrote the update method to use CM6 Compartments and StateEffects for dynamic configuration changes for the following features:
  • line numbers
  • wrapping
  • language
  • read-only
  • completions
• Replaced the CM5 view creation logic with CM6 EditorView instantiation and state creation (_createEditorState).
• Implemented language switching using _getLanguageExtension and the _languageCompartment.
• Autocomplete
  • Rewrote completion logic using CM6's autocompletion extension
  • Removed CM5 hint-related code.
  • Adapted _showDiagnostics to use CM6 Decorations and StateField.
• Reimplemented hide/fold pragma logic
  • using CM6 Decorations, WidgetType, and Annotations.
• Removed CM5-specific methods and event listeners (e.g., _onRenderLine).
• Added createRenderRoot to handle shadow root adoption for the EditorView
  • This was done to shore up some issues with the shadow root not being available in certain instances at connectedCallback()

playground-styles.css

Deleted this file entirely. Instead manually wrote the .css.ts file's style overrides.

src/playground-styles.ts

• Defines the editor's base styles and syntax highlighting theme.
• Styles are adapted from the old playground-styles.css but use CodeMirror 6 class names
• unlike before, it's not the styles + overrides, but rather JUST the overrides + css custom props

package.json

• Removed CodeMirror 5 related packages (@types/codemirror, codemirror-grammar-mode, google_modes).
• Added numerous CodeMirror 6 packages (@codemirror/*, @lezer/*).
• Updated the main codemirror dependency to ^6.0.1.
• Added codemirror-5 as a git dependency, for theme generation compatibility.
• Updated versions and integrity hash
• Removed build scripts related to CM5 (build:styles-module, build:codemirror).
• Updated wireit configurations to remove dependencies on the deleted build scripts.

rollup.config.codemirror.js

Deleted this file. It was responsible for bundling CodeMirror 5 and its addons.

rollup.config.styles.js

Deleted this file. It was used to process playground-styles.css into a TypeScript module.

scripts/theme-generator.js

Updated the script to read theme files from the codemirror-5/theme directory instead of codemirror/theme, reflecting the aliased package name for the old version.

src/_codemirror

Deleted this directory. This was the entry point for the custom CodeMirror 5 ESM-ified bundle.

src/cm-lang-lit.ts

• Defines custom CodeMirror 6 language support for Lit templates
  • html, css, svg, mathml within JavaScript and TypeScript
• exports language definitions:
  • litLanguage
  • litJsxLanguage
  • A main lit() language support function.

src/configurator/highlight-tokens.ts

• Updated the cmClass property for each token definition to match the new token class names generated by CodeMirror 6's classHighlighter
  • e.g., cm-keyword changed to tok-keyword
• Added a new synBool token.

src/configurator/playground-theme-detector.ts

• Removed logic specific to CodeMirror 5's rendering (viewportMargin).
• Added a mapping (tokenToCssProperty) to translate CM6 token names back to the existing CSS custom property names for compatibility.
• Updated the logic for extracting token classes to handle both cm- and tok- prefixes.
• Adjusted the text processing logic to better match how CM6 structures its highlighted output (e.g., handling #id in CSS).

src/internal/codemirror.ts

Deleted this file. It previously exported the CodeMirror 5 global object.

[e111077]

heya @justinfagnani @aomarks, I've added a summary to my description in the order of what files I think are important in this PR