Initial commit: The Daily EPUB full implementation

Full implementation of a personalized daily newspaper delivered as an
EPUB.

Articles are pulled from a local self-hosted Miniflux instance, enriched
with comments, summarized and filtered by DeepSeek AI, and then
assembled into two EPUB editions: standard and optimized for the Xteink
X4 e-ink reader. Both are served by the local self-hosted BookOrbit OPDS
server in a separate library. Then the X4 edition is futher converted to
XTC format and served over a separate OPDS server hosted by the Rust
binary. Runs are tracked in a local SQLite database so runs are
idempotent per date.

Full documentation of the plan is in docs/plans and setup and install
instructions are in the README.md file.

src/epub/templates/world_briefing.xhtml

@@ -0,0 +1,10 @@
+{% extends "base.xhtml" %}
+{% block body_class %}world-briefing{% endblock %}
+{% block content %}
+      <h1>World Briefing</h1>
+      <p class="dateline">{{ display_date }}</p>
+      <hr class="rule"/>
+      <div class="world-body">
+{{ body_html|safe }}
+      </div>
+{% endblock %}