refactor(agents): introduce chat/ category; dissolve top-level agents/shared

Recursive shared-folder rule: a shared/ must be shared by ALL siblings at its
level. The kernel (context, compaction, retry_after, web_search) was shared by
only 2 of the agents -- anonymous_chat + multi_agent_chat -- never by podcaster
or video_presentation. Those 2 are the "chat" category, so their shared code
belongs in that category's shared/, not the top-level one.

  app/agents/anonymous_chat/   -> app/agents/chat/anonymous_chat/
  app/agents/multi_agent_chat/ -> app/agents/chat/multi_agent_chat/
  app/agents/shared/           -> app/agents/chat/shared/   (anon<->mac kernel)

Top-level app/agents/shared/ is gone: nothing was shared across all three
categories (chat / podcaster / video_presentation).

~289 import sites rewritten (app.agents.{anonymous_chat,multi_agent_chat,shared}
-> app.agents.chat.*); all moves are git renames (history preserved).
app/agents/ now: chat/, podcaster/, video_presentation/, runtime/.

surfsense_backend/app/services/llm_service.py

@@ -204,7 +204,9 @@ async def validate_llm_config(
         if litellm_params:
             litellm_kwargs.update(litellm_params)
 
-        from app.agents.multi_agent_chat.shared.llm_config import SanitizedChatLiteLLM
+        from app.agents.chat.multi_agent_chat.shared.llm_config import (
+            SanitizedChatLiteLLM,
+        )
 
         llm = SanitizedChatLiteLLM(**litellm_kwargs)
 
@@ -379,7 +381,7 @@ async def get_search_space_llm_instance(
             if disable_streaming:
                 litellm_kwargs["disable_streaming"] = True
 
-            from app.agents.multi_agent_chat.shared.llm_config import (
+            from app.agents.chat.multi_agent_chat.shared.llm_config import (
                 SanitizedChatLiteLLM,
             )
 
@@ -460,7 +462,9 @@ async def get_search_space_llm_instance(
         if disable_streaming:
             litellm_kwargs["disable_streaming"] = True
 
-        from app.agents.multi_agent_chat.shared.llm_config import SanitizedChatLiteLLM
+        from app.agents.chat.multi_agent_chat.shared.llm_config import (
+            SanitizedChatLiteLLM,
+        )
 
         return SanitizedChatLiteLLM(**litellm_kwargs)
 
@@ -582,7 +586,7 @@ async def get_vision_llm(
             if global_cfg.get("litellm_params"):
                 litellm_kwargs.update(global_cfg["litellm_params"])
 
-            from app.agents.multi_agent_chat.shared.llm_config import (
+            from app.agents.chat.multi_agent_chat.shared.llm_config import (
                 SanitizedChatLiteLLM,
             )
 
@@ -638,7 +642,9 @@ async def get_vision_llm(
         if vision_cfg.litellm_params:
             litellm_kwargs.update(vision_cfg.litellm_params)
 
-        from app.agents.multi_agent_chat.shared.llm_config import SanitizedChatLiteLLM
+        from app.agents.chat.multi_agent_chat.shared.llm_config import (
+            SanitizedChatLiteLLM,
+        )
 
         return SanitizedChatLiteLLM(**litellm_kwargs)
 
@@ -683,7 +689,7 @@ def get_planner_llm() -> ChatLiteLLM | None:
     Callers MUST fall back to their chat LLM when this returns ``None`` so
     deployments without a planner config keep working unchanged.
     """
-    from app.agents.multi_agent_chat.shared.llm_config import (
+    from app.agents.chat.multi_agent_chat.shared.llm_config import (
         create_chat_litellm_from_config,
     )
 

surfsense_backend/app/services/provider_capabilities.py

@@ -53,7 +53,7 @@ logger = logging.getLogger(__name__)
 #
 # Owned here because ``app.services.provider_capabilities`` is the
 # only edge that's safe to call from ``app.config``'s YAML loader at
-# class-body init time. ``app.agents.multi_agent_chat.shared.llm_config`` re-exports
+# class-body init time. ``app.agents.chat.multi_agent_chat.shared.llm_config`` re-exports
 # this constant under the historical ``PROVIDER_MAP`` name; placing the
 # map there directly would re-introduce the
 # ``app.config -> ... -> deliverables/tools/generate_image ->

surfsense_backend/app/services/revert_service.py

@@ -38,7 +38,7 @@ from typing import Any, Literal
 from sqlalchemy import delete, select
 from sqlalchemy.ext.asyncio import AsyncSession
 
-from app.agents.multi_agent_chat.shared.path_resolver import (
+from app.agents.chat.multi_agent_chat.shared.path_resolver import (
     DOCUMENTS_ROOT,
     safe_filename,
     safe_folder_segment,

surfsense_backend/app/services/user_tool_allowlist.py

@@ -16,10 +16,10 @@ from sqlalchemy import select
 from sqlalchemy.ext.asyncio import AsyncSession
 from sqlalchemy.orm.attributes import flag_modified
 
-from app.agents.multi_agent_chat.constants import (
+from app.agents.chat.multi_agent_chat.constants import (
     CONNECTOR_TYPE_TO_CONNECTOR_AGENT_MAPS,
 )
-from app.agents.multi_agent_chat.shared.permissions import Rule, Ruleset
+from app.agents.chat.multi_agent_chat.shared.permissions import Rule, Ruleset
 from app.db import SearchSourceConnector, async_session_maker
 
 logger = logging.getLogger(__name__)