Add Claude Code memory files for AI-assisted development (#14078)

Add `.claude/` directory with path-scoped rule files providing context-aware guidance for Claude Code across the codebase:
- Lua filter development patterns and pipeline architecture
- Format handler conventions and registration
- Test infrastructure (smoke, Playwright, TypeScript, smoke-all)
- Deno/TypeScript conventions and the runtime abstraction layer
- Render pipeline architecture
- Changelog entry formatting and Zod schema usage

Add `llm-docs/testing-patterns.md` with detailed test reference, `dev-docs/claude-code-setup.md` contributor guide, and `dev-docs/debugging-flaky-tests.md` flaky test methodology. 

Add AI-Assisted Development section to CONTRIBUTING.md.

Rules use `paths:` frontmatter for conditional loading, keeping context usage efficient. All claims verified against the codebase by automated review agents.

-----

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: cderv

.claude/CLAUDE.md

@@ -0,0 +1,275 @@
+# CLAUDE.md
+
+This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
+
+## Project Overview
+
+Quarto is an open-source scientific and technical publishing system built on Pandoc. The CLI is written in TypeScript/Deno with Lua filters for document processing.
+
+### Versions
+
+Latest stable is the version at: <https://quarto.org/docs/download/_download.json>. Latest prerelease is at: <https://quarto.org/docs/download/_prerelease.json>
+
+## Setup & Configuration
+
+### Initial Setup
+
+```bash
+# Clone and configure (downloads Deno, dependencies, and sets up symlink)
+./configure.sh         # Linux/macOS
+./configure.cmd        # Windows
+
+# The configure script:
+# - Downloads and installs Deno to package/dist/bin/tools/
+# - Downloads Deno standard library
+# - Runs quarto-bld configure
+# - Vendors TypeScript dependencies
+# - Creates symlink to quarto in your PATH
+```
+
+After configuration, the development version can be run via:
+
+- `quarto` command (if symlink configured)
+- `package/dist/bin/quarto` (Linux/macOS) or `package/dist/bin/quarto.cmd` (Windows)
+
+### Configuration Files
+
+- `configuration` - Version numbers for all binary and JavaScript dependencies (Deno, Pandoc, Dart Sass, etc.)
+- `deno.jsonc` - Auto-generated Deno configuration (see dev-docs/update-deno_jsonc.md)
+- `src/import_map.json` - Deno import mappings
+- `src/dev_import_map.json` - Development import mappings
+
+## Building & Testing
+
+### Build Commands
+
+```bash
+# Run the build script (TypeScript-based)
+package/src/quarto-bld configure    # Configure/bootstrap
+package/src/quarto-bld prepare      # Prepare distribution
+```
+
+### Building Schemas and Artifacts
+
+Use the `dev-call` command with `build-artifacts` argument:
+
+```bash
+# Linux/macOS
+package/dist/bin/quarto dev-call build-artifacts
+
+# Windows
+package/dist/bin/quarto.cmd dev-call build-artifacts
+```
+
+This command regenerates:
+
+- JSON schemas in `src/resources/schema/json-schemas.json`
+- Zod schemas in `src/resources/types/zod/schema-types.ts`
+- TypeScript type definitions in `src/resources/types/schema-types.ts`
+- Editor tooling files (VSCode IntelliSense, YAML intelligence)
+
+### Running Tests
+
+Tests live in `tests/` and require R, Python, and Julia. See `.claude/rules/testing/overview.md` for commands, test types, dependencies, and debugging tips.
+
+```bash
+cd tests
+./run-tests.sh smoke/render/render.test.ts  # Linux/macOS
+.\run-tests.ps1 smoke/render/render.test.ts # Windows
+```
+
+### Feature Format Matrix
+
+The feature format matrix in `dev-docs/feature-format-matrix/` documents and tests feature support across all output formats.
+
+- Test documents organized by feature in `qmd-files/` subdirectories
+- Quality ratings in format metadata: `0` (broken/partial), `1` (good), `2` (excellent)
+- Runs on CI via `.github/workflows/test-ff-matrix.yml`
+
+## Architecture
+
+### Entry Point & Commands
+
+- `src/quarto.ts` - Main CLI entry point
+- `src/command/command.ts` - Command registration
+- Commands are organized in `src/command/*/cmd.ts` files:
+  - `render/` - Core rendering functionality
+  - `preview/` - Live preview server
+  - `publish/` - Publishing to various platforms
+  - `create/` and `add/` - Project/extension scaffolding
+  - `tools/`, `install/`, `check/` - Utilities
+
+### Core Systems
+
+**Project System** (`src/project/`)
+
+- `types/` - Project type implementations (book, website, manuscript, etc.)
+- Project types are registered via `project/types/register.ts`
+- Each type defines metadata, rendering behavior, and output structure
+
+**Format System** (`src/format/`)
+
+- Format handlers for different output types (HTML, PDF, DOCX, reveal.js, etc.)
+- `formats.ts` - Format registry and resolution
+- `format-handlers.ts` - Common format handling logic
+
+**Filter System** (`src/resources/filters/`)
+
+- Lua filters process Pandoc AST during rendering
+- `main.lua` - Entry point for filter chain
+- Organized by function: `crossref/`, `layout/`, `quarto-pre/`, `quarto-post/`, `quarto-finalize/`
+- Custom AST nodes in `customnodes/`
+- Common utilities in `common/`
+
+**Execution Engines** (`src/execute/`)
+
+- Integration with Jupyter, Knitr, and Observable for code execution
+- Engine-specific handling for Python, R, Julia, and JavaScript
+
+**Resources** (`src/resources/`)
+
+- Static assets, templates, and bundled libraries
+- Format-specific resources (HTML, PDF, reveal.js templates)
+- Extensions (Confluence, Docusaurus, etc.)
+- Pandoc datadir customizations
+
+### Key Subsystems
+
+**Preview System** (`src/preview/`)
+
+- Development server with live reload
+- Watches for file changes and re-renders
+
+**Publishing System** (`src/publish/`)
+
+- Platform-specific publishers (Netlify, GitHub Pages, Confluence, etc.)
+- Account management and deployment logic
+
+**Extension System** (`src/extension/`)
+
+- Quarto extensions (filters, formats, shortcodes)
+- Extension discovery, installation, and management
+
+### Package/Distribution
+
+- `package/` - Packaging and distribution scripts
+- `package/src/quarto-bld` - Build orchestration script (TypeScript)
+- Platform-specific packaging in `package/src/{linux,macos,windows}/`
+
+## Development Patterns
+
+### Debugging Flaky Tests
+
+Comprehensive methodology for debugging flaky tests documented in [dev-docs/debugging-flaky-tests.md](../dev-docs/debugging-flaky-tests.md).
+
+Key phases:
+1. Reproduce locally (outside CI)
+2. Binary search to isolate culprit test
+3. Narrow down within test file
+4. Understand state change
+5. Identify root cause
+6. Verify solution
+
+### TypeScript/Deno Conventions
+
+- Use Deno-native APIs (avoid Node.js APIs)
+- Import maps resolve dependencies (see `src/import_map.json`)
+- Cliffy library used for CLI parsing
+- File paths in imports must include `.ts` extension
+
+### Lua Filter Development
+
+- Filters run during Pandoc processing pipeline
+- Use `quarto` Lua module for Quarto-specific APIs
+- Common utilities in `src/resources/filters/common/`
+- Filters are chained together in `main.lua`
+- Documentation: <https://quarto.org/docs/extensions/lua-api.html>
+
+### Adding New Commands
+
+1. Create command file in `src/command/<name>/cmd.ts`
+2. Export command using Cliffy's `Command` API
+3. Register in `src/command/command.ts`
+
+### Adding New Project Types
+
+1. Create implementation in `src/project/types/<name>/`
+2. Implement `ProjectType` interface
+3. Register in `src/project/types/register.ts`
+
+### Adding New Formats
+
+1. Create format definition in `src/format/<name>/`
+2. Implement format handler
+3. Register in `src/format/imports.ts`
+
+### LaTeX Error Detection
+
+LaTeX error pattern maintenance is documented in [dev-docs/tinytex-pattern-maintenance.md](../dev-docs/tinytex-pattern-maintenance.md).
+
+- Patterns inspired by TinyTeX's comprehensive regex.json
+- Automated daily verification workflow checks for TinyTeX pattern updates
+- Pattern location: `src/command/render/latexmk/parse-error.ts`
+- Verification workflow: `.github/workflows/verify-tinytex-patterns.yml`
+
+## Important Conventions
+
+- Main branch: `main`
+- Version defined in `configuration` file in `QUARTO_VERSION` field
+- Binary dependencies (Deno, Pandoc, etc.) versions in `configuration`
+- Use `quarto-bld` for build operations, not direct Deno commands
+- Lua filters use Pandoc's filter infrastructure
+- TypeScript types for Lua APIs in `src/resources/lua-types/`
+
+### Changelog Conventions
+
+- Changelog files live in `news/changelog-{version}.md` (e.g., `changelog-1.9.md`)
+- Check `configuration` file for current `QUARTO_VERSION`
+- See `.claude/rules/changelog.md` for comprehensive conventions (section hierarchy, entry format, backports, regression fixes)
+
+## Key File Paths
+
+- Quarto binary: `package/dist/bin/quarto` (Linux/macOS) or `package/dist/bin/quarto.cmd` (Windows)
+- Deno binary: `package/dist/bin/tools/<arch>/deno`
+- Distribution output: `package/dist/`
+- Vendored dependencies: `src/vendor/`
+
+## Documentation
+
+- Documentation is at <https://quarto.org> with a sitemap at <https://quarto.org/sitemap.xml>
+- Prerelease docs: <https://prerelease.quarto.org/> for features in dev versions
+- Dev documentation in `dev-docs/` includes:
+  - Checklists for releases and backports
+  - Dependency update procedures
+  - Internals guides
+  - Performance monitoring
+
+## Contributing
+
+See CONTRIBUTING.md for pull request guidelines. Significant changes require a signed contributor agreement (individual or corporate).
+
+## Maintaining Memory Files
+
+This project uses Claude Code memory files for AI-assisted development. When updating memory files:
+
+- **Add new feature area?** Create `.claude/rules/<feature>/feature-name.md` with `paths:` frontmatter
+- **Update existing feature?** Edit the relevant rule file
+- **Deep dive doc needed?** Place it in `llm-docs/` and reference from rules
+
+**Memory file types:**
+
+| Location | When Loaded | Use For |
+|----------|-------------|---------|
+| `.claude/CLAUDE.md` | Always | Project overview, essential commands |
+| `.claude/rules/<feature>/` | When paths match | Feature-specific conventions |
+| `llm-docs/` | When explicitly read | Architectural deep dives |
+
+**Personal overrides:** Create `CLAUDE.local.md` (gitignored) for personal preferences like preferred shell syntax or workflow customizations. This file is loaded alongside the project CLAUDE.md but won't be committed.
+
+For setup details, see [dev-docs/claude-code-setup.md](../dev-docs/claude-code-setup.md).
+
+## Additional Resources
+
+- **LLM Documentation**: `llm-docs/` contains AI-specific guidance for working with the codebase
+- **Rules Files**: `.claude/rules/` contains conditional guidance for specific file patterns
+- **DeepWiki**: <https://deepwiki.com/quarto-dev/quarto-cli> for AI-indexed documentation

.claude/rules/changelog.md

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+---
+paths:
+  - news/**
+---
+
+# Changelog Conventions
+
+## File Organization
+
+- One file per major.minor version: `news/changelog-{version}.md` (e.g., `changelog-1.9.md`)
+- Check `configuration` file for current `QUARTO_VERSION`
+- First line: `All changes included in {version}:`
+
+## Section Hierarchy (strict order)
+
+1. **`## Regression fixes`** - Always FIRST if present
+2. **`## Dependencies`** - Bundled tool updates
+3. **`## Formats`** - By output format (H3 subsections)
+4. **`## Projects`** - By project type (H3 subsections)
+5. **`## Publishing`** - By platform (H3 subsections)
+6. **`## Lua API`** - Filter API changes
+7. **`## Commands`** - CLI commands (H3 subsections)
+8. **`## Extensions`** - Extension system changes
+9. **`## Engines`** - Execution engines (H3 subsections)
+10. **`## Other fixes and improvements`** - Always LAST
+
+### Format Subsections
+Use H3 headings with backtick-wrapped names:
+```markdown
+### `html`
+### `typst`
+### `pdf`
+```
+
+## Entry Format
+
+```markdown
+- ([#issue](url)): Description ending with period.
+```
+
+For external contributors (not core team):
+```markdown
+- ([#issue](url)): Description. (author: @username)
+```
+
+**Variations:**
+- Pull requests: `([#13441](https://github.com/quarto-dev/quarto-cli/pull/13441))`
+- External repos: `([rstudio/tinytex-releases#49](url))`
+- No issue/PR (rare): Reference commit hash instead: `([commit](https://github.com/quarto-dev/quarto-cli/commit/abc123))`
+
+## Writing Entries
+
+**Language patterns:**
+- **Fixes:** Start with "Fix" - describe what was broken
+  - "Fix `icon=false` not working with typst format."
+- **Enhancements:** Start with "Add" or "Support" - describe what was added
+  - "Add support for `icon=false` in callouts."
+- **Updates:** Start with "Update"
+  - "Update `pandoc` to 3.8.3"
+
+**Style:**
+- Use backticks for code/options: `` `icon=false` ``
+- Period at end of every description
+- Author attribution `(author: @username)` for **external contributors only** - do NOT add for quarto-cli core team members
+
+## Regression Fixes
+
+**What qualifies:** Bugs introduced in recent versions (same major.minor)
+
+**Placement:** Always at TOP of the file, before Dependencies
+
+**Workflow:** If you initially place an entry elsewhere and later determine it's a regression, move it to the Regression fixes section
+
+## Backports
+
+When a fix is backported to a stable branch:
+1. Entry exists in current version changelog (e.g., `changelog-1.9.md`)
+2. **Also add entry to stable version changelog** (e.g., `changelog-1.8.md`)
+
+## What NOT to Put Here
+
+**Highlights** are NOT changelog entries. They are:
+- Promotional content for release announcements
+- Managed in quarto-web: `docs/prerelease/{version}/_highlights.qmd`
+- Separate from technical changelog
+
+## Publication
+
+Changelogs are published to quarto.org via:
+- GitHub release attaches `changelog.md` asset
+- quarto-web fetches and displays at `/docs/download/changelog/{version}/`