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_email_attachment_text.py

@@ -16,7 +16,7 @@ def test_text_and_truncation(tmp_path):
 
 
 def test_real_pdf_text(tmp_path):
-    import fitz
+    fitz = pytest.importorskip('fitz')  # PyMuPDF is in requirements-optional.txt
     path = tmp_path / 'payslip.pdf'
     with fitz.open() as doc:
         page = doc.new_page()
@@ -38,7 +38,7 @@ def test_blank_pdf_reports_ocr(tmp_path):
 
 
 def test_xlsx(tmp_path):
-    from openpyxl import Workbook
+    Workbook = pytest.importorskip('openpyxl').Workbook  # requirements-optional.txt
     path = tmp_path / 'expenses.xlsx'
     book = Workbook()
     book.active.append(['Expenses', 12500])