merge: reconcile PR 40 with current lab

Integrate lab fff55a78 into PR #40 (cc25d5ba). Lab's modular email
backend/frontend, modular settings, split stylesheets (static/style.css
stays deleted), procfs compatibility, and request-scoped TurnContract
authority win; PR #40's routing classifiers, editor/email/task features,
and style.css changes are ported into lab's module and stylesheet homes.

Integration fixes:
- settings/api.js imports ui.js under its canonical versioned URL
- browser observations keep legacy CAPTCHA/access-block evidence
- artifact turns do not re-trigger broad-web research recovery
- env reference documents PR test-tool variables; page regenerated

PR #40 defects surfaced by lab gates and fixed here:
- web_fetch generic schema drops top-level anyOf (OpenAI contract);
  the compact preview contract still requires url or urls
- get_weather registered as a brokered network read
- new lazy editor modules precached for offline use
- SearXNG pin mirrored into GPU standalone compose files
- image model picker again skips offline endpoints

Tests updated where PR #40 changed behaviour on purpose, and PR tests
moved onto lab's document_source helpers.

tests/test_yoyo_builtin_theme.py

@@ -17,5 +17,9 @@ def test_agent_theme_inventory_includes_yoyo():
     interaction = (ROOT / "src/ai_interaction.py").read_text(encoding="utf-8")
     schemas = (ROOT / "src/tool_schemas.py").read_text(encoding="utf-8")
 
-    assert '"monolith", "yoyo"' in interaction
+    from src.theme_palette import THEME_PRESETS
+
+    # The agent's preset inventory is the shared palette module's tuple.
+    assert THEME_PRESETS[-2:] == ("monolith", "yoyo")
+    assert "from src.theme_palette import THEME_PRESETS" in interaction
     assert "blueprint, monolith, yoyo" in schemas