chore: track all project map and index files

Add generated .pi-map.md and .pi-map.index.md files across the repository
so the project navigation maps are shared and versioned. These artifacts
are maintained by project_map_init/patch/validate and must be kept in
sync with source edits.

Note: .cache/ remains ignored (added in previous commit).

docs/features/.pi-map.index.md

@@ -0,0 +1,28 @@
+# docs/features (index)
+dir: docs/features
+
+## role
+User-facing documentation for features of the "Headquarter" developer platform application, covering authentication, project/repository management, git tools, web-based terminals, and workspace editing.
+## parent
+index: docs/.pi-map.index.md
+map: docs/.pi-map.md
+## children
+-
+## files
+- auth.md
+- git-history.md
+- projects.md
+- repositories.md
+- settings.md
+- ssh-keys.md
+- terminal-troubleshooting.md
+- terminal.md
+- tool-types.md
+- workspace.md
+## links
+index: docs/features/.pi-map.index.md
+map: docs/features/.pi-map.md
+## workflows
+-
+## dirty
+-

docs/features/.pi-map.md

@@ -0,0 +1,28 @@
+# docs/features
+dir: docs/features
+
+index: docs/features/.pi-map.index.md
+
+## role
+User-facing documentation for features of the "Headquarter" developer platform application, covering authentication, project/repository management, git tools, web-based terminals, and workspace editing.
+## files
+- auth.md | Documents the OAuth2 authentication system using Authentik for the Headquarter application | dep: Authentik, OAuth2, session cookies
+- git-history.md | Documents a Git history visualization UI feature showing commit graphs, branch filtering, and commit details with diff viewing | dep: Git, repositories API, branch selector UI component, diff syntax highlighter
+- projects.md | Documentation for project management functionality in a software application called Headquarter
+- repositories.md | Documents how to create, manage, and interact with Git repositories within a project-based system | dep: Git, SSH, GitHub, GitLab, API endpoints
+- settings.md | Documentation for user settings functionality in a Headquarter application, covering theme preferences, git identity, and default editor configuration.
+- ssh-keys.md | Document SSH key management functionality for git authentication in an application
+- terminal-troubleshooting.md | Provides troubleshooting guidance for diagnosing and resolving terminal connection and functionality issues in a web-based terminal system | dep: WebSocket, Docker, browser DevTools, API server, terminal session management
+- terminal.md | Documents terminal session functionality for browser-based interactive shell access to containerized tool instances
+- tool-types.md | Documents how to define, manage, and use development tool types in Headquarter using Docker Compose templates | dep: Docker Compose, YAML, git, VS Code Server, Jupyter Notebook
+- workspace.md | Documents a repository workspace file browser interface with repository/branch selection, file tree navigation, file viewing with syntax highlighting, and quick editing capabilities. | dep: Git, Repositories API, Git History, Git Repositories
+## arch
+Flat markdown documentation structure organized by feature domain, with each file independently documenting a specific subsystem; no code or cross-references, purely descriptive end-user guides for a containerized development environment platform.
+## tags
+git, terminal, documents, functionality, headquarter, application, ssh, tool
+## symbols
+-
+## workflows
+-
+## dirty
+-