feat: add project file system with CRUD, upload, inline editing, and video attachment support

- Add new `/projects/{slug}/files` endpoint group for per-project filesystem operations including directory and file CRUD, upload, and inline editing with public read and owner write access
- Extend attachment system to support video formats (webm, ogv, mov, m4v) with proper file icons and MIME types
- Implement configurable allowed file types via `allowed_file_types` site setting, replacing hardcoded `ALLOWED_UPLOAD_TYPES` with dynamic `allowed_extensions()` and `is_extension_allowed()` functions
- Add `delete_all_project_files()` call in `delete_content_item()` to clean up project files when a project is deleted
- Create database indexes on `project_files` table for `(project_uid, path)` and `(project_uid, parent_path)` to optimize file lookups
- Introduce `docs_prose.py` module with `render_prose()` function that renders Markdown content inside `data-render` divs using mistune, enabling dynamic prose rendering in documentation pages
- Enhance docs search with Markdown-aware text stripping (`_demarkdown()`) and improved HTML/script/style sanitization for better search indexing
- Update documentation API samples to reflect new attachment response fields (`is_image`, `is_video`, `mime_type`) and note video format support
- Update README to document the new project files endpoint and clarify AI gateway attribution for guest Devii sessions

devplacepy/templates/docs_base.html

@@ -2,6 +2,7 @@
 {% block extra_head %}
 <link rel="stylesheet" href="/static/css/sidebar.css">
 <link rel="stylesheet" href="/static/css/docs.css">
+<link rel="stylesheet" href="/static/css/components-docs.css">
 {% endblock %}
 {% block content %}
 <script>window.DEVPLACE_DOCS = {{ {
@@ -45,6 +46,8 @@
             {% include "docs/_search.html" %}
         {% elif kind == 'api' %}
             {% include "docs/_api_page.html" %}
+        {% elif prose_html %}
+            {{ prose_html | safe }}
         {% else %}
             {% include "docs/" ~ current ~ ".html" %}
         {% endif %}