feat: extract shared infrastructure from shared_lib

Phase 1-3 of decoupling plan:
- Shared DB, models, infrastructure, browser, config, utils
- Event infrastructure (domain_events outbox, bus, processor)
- Structured logging
- Generic container concept (container_type/container_id)
- Alembic migrations for all schema changes

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

browser/templates/oob_elements.html

@@ -0,0 +1,38 @@
+
+{% block oobs %}
+{% endblock %}
+
+<div
+  id="filter"
+  hx-swap-oob="outerHTML"
+>
+{% block filter %}
+{% endblock %}
+</div>
+
+
+
+<aside
+  id="aside"
+  hx-swap-oob="outerHTML"
+  class="hidden md:flex md:flex-col max-w-xs md:h-full md:min-h-0 mr-3"
+>
+{% block aside %}
+{% endblock %}
+</aside>
+
+<div id="root-menu" hx-swap-oob="outerHTML" class="md:hidden">
+  {% block mobile_menu %}
+  {% endblock %}
+</div>
+
+
+<section
+  id="main-panel"
+  class="flex-1 md:h-full md:min-h-0 overflow-y-auto overscroll-contain js-grid-viewport"
+>
+  {% block content %}
+
+  {% endblock %}
+
+</section>