[feat] plugin: AI summary of search results via local Ollama server

Add an optional, disabled-by-default plugin that shows an AI generated
summary at the top of the result page, generated by a (local) Ollama
server:

- async: the result page is never delayed; a client plugin streams the
  answer (NDJSON over a new /ai_summary endpoint) into a placeholder
  answer with a typing indicator, collapsed behind a More button, with
  an inline follow-up chat
- trigger: first page of general searches only, skipped when an infobox
  or instant answer already answers the query
- grounding (per-user preference): send the top result snippets as
  context, the model answers from them instead of its own knowledge
- configuration: new AI Summary preferences tab (server URL, model,
  grounding) with instance defaults in a new ai_summary: settings
  section; all three preferences can be locked for public instances

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

searx/result_types/__init__.py

@@ -19,6 +19,7 @@ __all__ = [
     "EngineResults",
     "AnswerSet",
     "Answer",
+    "AiSummary",
     "Translations",
     "WeatherAnswer",
     "Code",
@@ -32,7 +33,7 @@ import typing as t
 import abc
 
 from ._base import Result, MainResult, LegacyResult
-from .answer import AnswerSet, Answer, Translations, WeatherAnswer
+from .answer import AnswerSet, Answer, AiSummary, Translations, WeatherAnswer
 from .keyvalue import KeyValue
 from .code import Code
 from .paper import Paper
@@ -49,6 +50,7 @@ class ResultList(list[Result | LegacyResult], abc.ABC):
         implemented)."""
 
         Answer = Answer
+        AiSummary = AiSummary
         KeyValue = KeyValue
         Code = Code
         Paper = Paper

searx/result_types/answer.py

@@ -14,6 +14,10 @@ template.
    :members:
    :show-inheritance:
 
+.. autoclass:: AiSummary
+   :members:
+   :show-inheritance:
+
 .. autoclass:: Translations
    :members:
    :show-inheritance:
@@ -29,7 +33,7 @@ template.
 # pylint: disable=too-few-public-methods
 
 
-__all__ = ["AnswerSet", "Answer", "Translations", "WeatherAnswer"]
+__all__ = ["AnswerSet", "Answer", "AiSummary", "Translations", "WeatherAnswer"]
 
 from flask_babel import gettext
 import msgspec
@@ -92,6 +96,28 @@ class Answer(BaseAnswer, kw_only=True):
         return hash(self.answer)
 
 
+class AiSummary(BaseAnswer, kw_only=True):
+    """Placeholder for an AI generated summary of the search query
+    (:py:obj:`searx.plugins.ai_summary`).  The summary itself is fetched
+    asynchronously by the client after the result page has been rendered."""
+
+    # The answers of an AnswerSet are sorted by their template name; this
+    # template sorts before the other answer templates, the AI summary is
+    # therefore rendered first in the answer area.
+    template: str = "answer/ai_summary.html"
+
+    query: str
+    """The search query the summary is generated for."""
+
+    grounding: bool = False
+    """Ground the summary on the search results (user's preference)."""
+
+    def __hash__(self):
+        """The hash value of field *query* is the hash value of the
+        :py:obj:`AiSummary` object."""
+        return hash(self.query)
+
+
 class Translations(BaseAnswer, kw_only=True):
     """Answer type with a list of translations.