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.

docker-compose.gpu-amd.yml

@@ -133,7 +133,7 @@ services:
     # tag blocks the whole app from starting. 2026.6.2 crashes on boot with
     # `KeyError: 'default_doi_resolver'`, failing the healthcheck (issue #1414).
     # Bump this deliberately after verifying a newer tag boots clean.
-    image: docker.io/searxng/searxng:2026.5.31-7159b8aed
+    image: docker.io/searxng/searxng:2026.9.25-12f8b6515@sha256:5286edb35782454ab8a102c5eff6b54bff745853191b46aeead95f225aa6dfb6
     entrypoint:
       - /bin/sh
       - -c