feat(mem0-plugin): support self-hosted Mem0 server via MEM0_BASE_URL

Adds an optional MEM0_BASE_URL override (env var, falling back to
settings.json's base_url, defaulting to the hosted Platform unchanged)
so the plugin's REST-backed hooks can talk to a self-hosted server/
deployment instead of api.mem0.ai.

A new scripts/_api.py centralizes the hosted-vs-self-hosted protocol
differences (unversioned paths, X-API-Key auth, agent_id instead of
app_id) that every hook previously hardcoded, and all 9 urllib call
sites now route through it.

MCP tools have no self-hosted backend (server/ implements no MCP), so
they continue to talk to the hosted Platform regardless of
MEM0_BASE_URL; this is documented rather than silently left unclear.
Coding-category customization also has no self-hosted SDK equivalent
and now skips cleanly with a log message instead of failing.

Closes MEM-5647

integrations/mem0-plugin/scripts/session_timeline.py

@@ -11,51 +11,23 @@ Output: Compact timeline text to stdout (empty if nothing found)
 
 from __future__ import annotations
 
-import json
 import os
 import sys
-import urllib.request
 
 sys.path.insert(0, os.path.dirname(os.path.abspath(__file__)))
+from _api import fetch_recent
 from _formatting import TYPE_ICONS, format_age
 from _identity import resolve_api_key, resolve_user_id
 from _project import resolve_project_id
 
-API_URL = "https://api.mem0.ai"
 MAX_RECENT = 10
 MAX_SUMMARIES = 3
-FETCH_TIMEOUT = 5
 
 
 def fetch_recent_memories(api_key: str, user_id: str, project_id: str) -> list[dict]:
-    """Fetch the most recent memories for this project via GET list endpoint."""
+    """Fetch the most recent memories for this project."""
     global_search = os.environ.get("MEM0_GLOBAL_SEARCH", "false") == "true"
-
-    if global_search:
-        filters = {"OR": [{"user_id": "*"}]}
-    else:
-        filters = {"AND": [{"user_id": user_id}, {"app_id": project_id}]}
-
-    body = json.dumps({"filters": filters}).encode()
-    req = urllib.request.Request(
-        f"{API_URL}/v3/memories/?page=1&page_size={MAX_RECENT}",
-        data=body,
-        headers={
-            "Authorization": f"Token {api_key}",
-            "Content-Type": "application/json",
-        },
-        method="POST",
-    )
-    try:
-        with urllib.request.urlopen(req, timeout=FETCH_TIMEOUT) as r:
-            result = json.loads(r.read())
-            if isinstance(result, dict) and "results" in result:
-                return result["results"][:MAX_RECENT]
-            if isinstance(result, list):
-                return result[:MAX_RECENT]
-            return []
-    except Exception:
-        return []
+    return fetch_recent(api_key, user_id, project_id, top_k=MAX_RECENT, global_search=global_search)[:MAX_RECENT]
 
 
 def format_timeline(memories: list[dict]) -> str: