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/tests/unit/middleware/test_b_filesystem_path_resolution.py

@@ -6,9 +6,9 @@ Ported from the dead-twin suites:
 * ``tests/unit/middleware/test_filesystem_verification.py`` (desktop
   multi-root mount-prefix normalization)
 
-Both exercised ``app.agents.shared.middleware.filesystem`` (dead). This drives
+Both exercised ``app.agents.chat.shared.middleware.filesystem`` (dead). This drives
 the production free functions in
-``app.agents.multi_agent_chat.shared.middleware.filesystem.middleware`` instead.
+``app.agents.chat.multi_agent_chat.shared.middleware.filesystem.middleware`` instead.
 The functions only touch ``mw._filesystem_mode`` and ``mw._get_backend`` so we
 pass a lightweight fake ``mw`` rather than constructing the full middleware.
 """
@@ -20,17 +20,17 @@ from types import SimpleNamespace
 
 import pytest
 
-from app.agents.multi_agent_chat.shared.filesystem_selection import FilesystemMode
-from app.agents.multi_agent_chat.shared.middleware.filesystem.backends.multi_root_local_folder import (
+from app.agents.chat.multi_agent_chat.shared.filesystem_selection import FilesystemMode
+from app.agents.chat.multi_agent_chat.shared.middleware.filesystem.backends.multi_root_local_folder import (
     MultiRootLocalFolderBackend,
 )
-from app.agents.multi_agent_chat.shared.middleware.filesystem.middleware.mode import (
+from app.agents.chat.multi_agent_chat.shared.middleware.filesystem.middleware.mode import (
     default_cwd,
 )
-from app.agents.multi_agent_chat.shared.middleware.filesystem.middleware.namespace_policy import (
+from app.agents.chat.multi_agent_chat.shared.middleware.filesystem.middleware.namespace_policy import (
     check_cloud_write_namespace,
 )
-from app.agents.multi_agent_chat.shared.middleware.filesystem.middleware.path_resolution import (
+from app.agents.chat.multi_agent_chat.shared.middleware.filesystem.middleware.path_resolution import (
     current_cwd,
     get_contract_suggested_path,
     normalize_local_mount_path,

surfsense_backend/tests/unit/middleware/test_b_filesystem_rm_rmdir_cloud.py

@@ -1,9 +1,9 @@
 """Cloud-mode ``rm``/``rmdir`` staging tests for the LIVE filesystem middleware.
 
 Ported from the former ``tests/unit/agents/new_chat/test_rm_rmdir_cloud.py``,
-which exercised the *dead twin* ``app.agents.shared.middleware.filesystem``.
+which exercised the *dead twin* ``app.agents.chat.shared.middleware.filesystem``.
 This drives the production decomposed tools
-(``app.agents.multi_agent_chat.shared.middleware.filesystem``) instead: it
+(``app.agents.chat.multi_agent_chat.shared.middleware.filesystem``) instead: it
 builds the real middleware via ``build_filesystem_mw``, pulls the real ``rm`` /
 ``rmdir`` tools off it, and invokes their coroutines with a stubbed
 ``KBPostgresBackend`` + runtime so we can assert the end-of-turn staging
@@ -19,20 +19,20 @@ from unittest.mock import AsyncMock
 
 import pytest
 
-from app.agents.multi_agent_chat.shared.filesystem_selection import (
+from app.agents.chat.multi_agent_chat.shared.filesystem_selection import (
     FilesystemMode,
     FilesystemSelection,
 )
-from app.agents.multi_agent_chat.shared.middleware.filesystem import (
+from app.agents.chat.multi_agent_chat.shared.middleware.filesystem import (
     build_filesystem_mw,
 )
-from app.agents.multi_agent_chat.shared.middleware.filesystem.backends.kb_postgres import (
+from app.agents.chat.multi_agent_chat.shared.middleware.filesystem.backends.kb_postgres import (
     KBPostgresBackend,
 )
-from app.agents.multi_agent_chat.shared.middleware.filesystem.backends.resolver import (
+from app.agents.chat.multi_agent_chat.shared.middleware.filesystem.backends.resolver import (
     build_backend_resolver,
 )
-from app.agents.multi_agent_chat.shared.state.reducers import _CLEAR
+from app.agents.chat.multi_agent_chat.shared.state.reducers import _CLEAR
 
 pytestmark = pytest.mark.unit
 

surfsense_backend/tests/unit/middleware/test_b_filesystem_system_prompt.py

@@ -2,7 +2,7 @@
 
 Ported from ``TestModeSpecificPrompts`` in the former
 ``tests/unit/middleware/test_filesystem_middleware.py`` (which exercised the
-dead twin ``app.agents.shared.middleware.filesystem._build_filesystem_system_prompt``).
+dead twin ``app.agents.chat.shared.middleware.filesystem._build_filesystem_system_prompt``).
 
 These drive the production ``build_system_prompt`` so the prompt the model
 actually receives stays mode-scoped: cloud rules don't leak into desktop
@@ -18,8 +18,8 @@ from __future__ import annotations
 
 import pytest
 
-from app.agents.multi_agent_chat.shared.filesystem_selection import FilesystemMode
-from app.agents.multi_agent_chat.shared.middleware.filesystem.system_prompt import (
+from app.agents.chat.multi_agent_chat.shared.filesystem_selection import FilesystemMode
+from app.agents.chat.multi_agent_chat.shared.middleware.filesystem.system_prompt import (
     build_system_prompt,
 )
 

surfsense_backend/tests/unit/middleware/test_dedup_hitl_tool_calls.py

@@ -2,10 +2,10 @@ import pytest
 from langchain_core.messages import AIMessage
 from langchain_core.tools import StructuredTool
 
-from app.agents.multi_agent_chat.main_agent.middleware.dedup_hitl import (
+from app.agents.chat.multi_agent_chat.main_agent.middleware.dedup_hitl import (
     DedupHITLToolCallsMiddleware,
 )
-from app.agents.multi_agent_chat.shared.middleware.dedup_tool_calls import (
+from app.agents.chat.multi_agent_chat.shared.middleware.dedup_tool_calls import (
     wrap_dedup_key_by_arg_name,
 )
 

surfsense_backend/tests/unit/middleware/test_filesystem_backends.py

@@ -2,16 +2,16 @@ from pathlib import Path
 
 import pytest
 
-from app.agents.multi_agent_chat.shared.filesystem_selection import (
+from app.agents.chat.multi_agent_chat.shared.filesystem_selection import (
     ClientPlatform,
     FilesystemMode,
     FilesystemSelection,
     LocalFilesystemMount,
 )
-from app.agents.multi_agent_chat.shared.middleware.filesystem.backends.multi_root_local_folder import (
+from app.agents.chat.multi_agent_chat.shared.middleware.filesystem.backends.multi_root_local_folder import (
     MultiRootLocalFolderBackend,
 )
-from app.agents.multi_agent_chat.shared.middleware.filesystem.backends.resolver import (
+from app.agents.chat.multi_agent_chat.shared.middleware.filesystem.backends.resolver import (
     build_backend_resolver,
 )
 

surfsense_backend/tests/unit/middleware/test_kb_persistence_filesystem_parity.py

@@ -15,7 +15,7 @@ from unittest.mock import AsyncMock
 import numpy as np
 import pytest
 
-from app.agents.multi_agent_chat.shared.middleware import kb_persistence
+from app.agents.chat.multi_agent_chat.shared.middleware import kb_persistence
 from app.db import Document
 
 

surfsense_backend/tests/unit/middleware/test_kb_persistence_revisions.py

@@ -21,7 +21,7 @@ from unittest.mock import AsyncMock, MagicMock
 
 import pytest
 
-from app.agents.multi_agent_chat.shared.middleware import kb_persistence
+from app.agents.chat.multi_agent_chat.shared.middleware import kb_persistence
 
 pytestmark = pytest.mark.unit
 

surfsense_backend/tests/unit/middleware/test_knowledge_search.py

@@ -5,11 +5,11 @@ import json
 import pytest
 from langchain_core.messages import AIMessage, HumanMessage
 
-from app.agents.multi_agent_chat.shared.middleware import knowledge_search as ks
-from app.agents.multi_agent_chat.shared.middleware.filesystem.backends.document_xml import (
+from app.agents.chat.multi_agent_chat.shared.middleware import knowledge_search as ks
+from app.agents.chat.multi_agent_chat.shared.middleware.filesystem.backends.document_xml import (
     build_document_xml as _build_document_xml,
 )
-from app.agents.multi_agent_chat.shared.middleware.knowledge_search import (
+from app.agents.chat.multi_agent_chat.shared.middleware.knowledge_search import (
     KBSearchPlan,
     KnowledgePriorityMiddleware,
     _normalize_optional_date_range,

surfsense_backend/tests/unit/middleware/test_knowledge_tree.py

@@ -9,10 +9,10 @@ contract cannot silently regress.
 
 from __future__ import annotations
 
-from app.agents.multi_agent_chat.main_agent.middleware.knowledge_tree.middleware import (
+from app.agents.chat.multi_agent_chat.main_agent.middleware.knowledge_tree.middleware import (
     KnowledgeTreeMiddleware,
 )
-from app.agents.multi_agent_chat.shared.path_resolver import DOCUMENTS_ROOT
+from app.agents.chat.multi_agent_chat.shared.path_resolver import DOCUMENTS_ROOT
 
 
 def _compute(folder_paths: list[str], doc_paths: list[str]) -> set[str]:
@@ -88,7 +88,7 @@ class TestFormatTreeRendering:
         folder_paths: list[str],
         doc_specs: list[dict],
     ) -> str:
-        from app.agents.multi_agent_chat.shared.path_resolver import PathIndex
+        from app.agents.chat.multi_agent_chat.shared.path_resolver import PathIndex
 
         index = PathIndex(
             folder_paths={i + 1: p for i, p in enumerate(folder_paths)},

surfsense_backend/tests/unit/middleware/test_local_folder_backend.py

@@ -2,7 +2,7 @@ from pathlib import Path
 
 import pytest
 
-from app.agents.multi_agent_chat.shared.middleware.filesystem.backends.local_folder import (
+from app.agents.chat.multi_agent_chat.shared.middleware.filesystem.backends.local_folder import (
     LocalFolderBackend,
 )
 

surfsense_backend/tests/unit/middleware/test_multi_root_local_folder_backend.py

@@ -2,7 +2,7 @@ from pathlib import Path
 
 import pytest
 
-from app.agents.multi_agent_chat.shared.middleware.filesystem.backends.multi_root_local_folder import (
+from app.agents.chat.multi_agent_chat.shared.middleware.filesystem.backends.multi_root_local_folder import (
     MultiRootLocalFolderBackend,
 )