Fix archive plugins for НЭБ and Alib; add network integration tests

- html_scraper: add img_alt strategy (НЭБ titles from <img alt>), bold_text
  strategy (Alib entries from <p><b>), Windows-1251 encoding support,
  _cls_inner_texts() helper that strips inner HTML tags
- rsl: rewrite to POST SearchFilterForm[search] with CSRF token and CQL
  title:(words) AND author:(word) query format
- config: update rusneb (img_alt + correct author_class) and alib_web
  (encoding + bold_text) to match fixed plugin strategies
- tests: add tests/test_archives.py with network-marked tests for all six
  archive plugins; НЛР and ШПИЛ marked xfail (endpoints return HTTP 404)
- presubmit: exclude network tests from default run (-m "not network")

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

config/functions.default.yaml

@@ -64,8 +64,8 @@ functions:
       config:
         url: "https://rusneb.ru/search/"
         search_param: q
-        title_class: "title"
-        author_class: "author"
+        img_alt: true
+        author_class: "search-list__item_subtext"
 
     alib_web:
       name: "Alib (web)"
@@ -77,8 +77,8 @@ functions:
         url: "https://www.alib.ru/find3.php4"
         search_param: tfind
         extra_params: {f: "5", s: "0"}
-        link_href_pattern: "t[a-z]+\\.phtml"
-        author_class: "aut"
+        encoding: "cp1251"
+        bold_text: true
 
     nlr:
       name: "НЛР"