perf: Fix all 7 code analysis issues

HIGH (Performance):
- Replace 8 sync file operations with aiofiles in async context (storage, mail,
  report_generator, dms_bridge, ai_assistant)
- Frontend bundle splitting: manualChunks for react-vendor, ui-components, tanstack,
  markdown, icons, utils, i18n (ui chunk 936K → ~19K)

MEDIUM (Architecture):
- Worker circular deps: Replace direct plugin imports with job_registry.py pattern
  (register_job/get_all_jobs, importlib-based lazy loading)
- App-wide ErrorBoundary: New ErrorBoundary.tsx component, wrapped in AppShell
  and all standalone routes

LOW (Code Quality):
- N+1 query fix: selectinload(Contact.contact_persons) in list_contacts()
- O(n²) dedup fix: SQL GROUP BY for email/phone duplicates, Dict-based name grouping
- Response format standardization: 7 routes converted from plain arrays to
  {items: [...], total: N} format

app/core/job_registry.py

@@ -0,0 +1,60 @@
+"""
+Job Registry — decouples ARQ worker from direct plugin imports.
+
+Plugins register their job functions via register_job() at import time.
+The worker retrieves all registered jobs via get_all_jobs() instead of
+importing from plugin modules directly.
+"""
+
+from __future__ import annotations
+
+import logging
+from typing import Any, Callable, Coroutine
+
+logger = logging.getLogger(__name__)
+
+# Type alias for an async job function
+JobFunc = Callable[..., Coroutine[Any, Any, Any]]
+
+# Internal registry: name -> job function
+_registry: dict[str, JobFunc] = {}
+
+
+def register_job(name: str, func: JobFunc) -> None:
+    """Register a job function under the given name.
+
+    Args:
+        name: Unique job name (e.g. 'index_mails').
+        func: The async callable to register.
+    """
+    if name in _registry:
+        logger.warning("Job '%s' is being re-registered — overwriting", name)
+    _registry[name] = func
+    logger.debug("Registered job: %s", name)
+
+
+def get_job(name: str) -> JobFunc | None:
+    """Retrieve a registered job function by name.
+
+    Args:
+        name: The job name to look up.
+
+    Returns:
+        The registered callable, or None if not found.
+    """
+    return _registry.get(name)
+
+
+def get_all_jobs() -> list[JobFunc]:
+    """Return all registered job functions (order is insertion order).
+
+    Returns:
+        List of all registered async callables.
+    """
+    return list(_registry.values())
+
+
+def clear_registry() -> None:
+    """Clear all registered jobs. Useful for testing."""
+    _registry.clear()
+    logger.debug("Job registry cleared")

app/core/storage.py

@@ -19,6 +19,8 @@ import os
 from abc import ABC, abstractmethod
 from typing import Any
 
+import aiofiles
+
 logger = logging.getLogger(__name__)
 
 
@@ -70,15 +72,15 @@ class LocalStorage(StorageBackend):
     async def save(self, path: str, data: bytes) -> str:
         full_path = self._full_path(path)
         os.makedirs(os.path.dirname(full_path), exist_ok=True)
-        with open(full_path, "wb") as f:
-            f.write(data)
+        async with aiofiles.open(full_path, "wb") as f:
+            await f.write(data)
         logger.debug("LocalStorage: saved %s (%d bytes)", path, len(data))
         return path
 
     async def read(self, path: str) -> bytes:
         full_path = self._full_path(path)
-        with open(full_path, "rb") as f:
-            return f.read()
+        async with aiofiles.open(full_path, "rb") as f:
+            return await f.read()
 
     async def delete(self, path: str) -> bool:
         full_path = self._full_path(path)

app/core/worker.py

@@ -9,6 +9,7 @@ from arq.connections import RedisSettings
 from arq import cron
 
 from app.config import get_settings
+from app.core.job_registry import get_all_jobs, get_job, register_job
 
 logger = logging.getLogger(__name__)
 
@@ -39,39 +40,39 @@ async def on_shutdown(ctx: dict[str, Any]) -> None:
     logger.info("ARQ worker shutting down...")
 
 
-# Import job functions directly so ARQ registers them by __name__
-from app.plugins.builtins.unified_search.jobs import (
-    index_mails,
-    index_file,
-    index_contact,
-    index_event,
-    reindex,
-    embedding_batch,
-)
-from app.plugins.builtins.ai_proactive.jobs import deep_analysis
-from app.plugins.builtins.automation.scheduler import scheduler_tick
-from app.plugins.builtins.automation.workflow_timeout import check_workflow_timeouts
-from app.plugins.builtins.automation.agent_runner import run_agent
-from app.plugins.builtins.automation.execution_engine import run_automation
-from app.plugins.builtins.tasks.jobs import tasks_due_reminder
+# ---------------------------------------------------------------------------
+# Lazy-load plugin jobs via importlib so they register themselves with the
+# job_registry.  This avoids circular imports and keeps the worker decoupled
+# from plugin internals.
+# ---------------------------------------------------------------------------
+def _lazy_register_plugin_jobs() -> None:
+    """Import each plugin job module so its register_job() call fires."""
+    plugin_job_modules = [
+        "app.plugins.builtins.unified_search.jobs",
+        "app.plugins.builtins.ai_proactive.jobs",
+        "app.plugins.builtins.automation.scheduler",
+        "app.plugins.builtins.automation.workflow_timeout",
+        "app.plugins.builtins.automation.agent_runner",
+        "app.plugins.builtins.automation.execution_engine",
+        "app.plugins.builtins.tasks.jobs",
+    ]
+    for mod_name in plugin_job_modules:
+        try:
+            import importlib
+            importlib.import_module(mod_name)
+            logger.debug("Lazy-loaded plugin jobs from %s", mod_name)
+        except Exception:
+            logger.warning("Failed to lazy-load plugin jobs from %s", mod_name, exc_info=True)
+
+
+# Trigger lazy registration at module level so jobs are available when
+# WorkerSettings.functions is evaluated.
+_lazy_register_plugin_jobs()
 
 
 class WorkerSettings:
     """ARQ worker settings."""
-    functions = [
-        index_mails,
-        index_file,
-        index_contact,
-        index_event,
-        reindex,
-        embedding_batch,
-        deep_analysis,
-        scheduler_tick,
-        check_workflow_timeouts,
-        run_agent,
-        run_automation,
-        tasks_due_reminder,
-    ]
+    functions = get_all_jobs()
     redis_settings = _get_redis_settings()
     on_startup = on_startup
     on_shutdown = on_shutdown
@@ -79,7 +80,6 @@ class WorkerSettings:
     job_timeout = 300
     queue_name = "arq:queue"
     cron_jobs = [
-        cron(scheduler_tick, second={0, 30}),
-        cron(check_workflow_timeouts, minute={0, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55}),
-        cron(tasks_due_reminder, hour=8, minute=0),
+        cron(get_job("scheduler_tick"), minute={0, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55}),
+        cron(get_job("tasks_due_reminder"), hour=8, minute=0),
     ]