fix(honcho): resolve sessions against agent cwd, not process cwd

The Honcho provider resolved per-repo/per-directory session names from
os.getcwd(), which is the backend process launch directory on
Desktop/gateway hosts (typically $HOME), not the user's workspace. With
a manual sessions map entry for the home directory, every Desktop
conversation landed in that fallback bucket instead of the project's
per-repo session.

Use agent.runtime_cwd.resolve_agent_cwd() — the same single source of
truth already used for system-prompt and context-file discovery — so
Honcho session routing agrees with everything else about where the
agent logically lives. It honors the pinned session cwd, then
TERMINAL_CWD, then the launch directory; CLI sessions launched inside a
project resolve identically either way.

Adds a regression covering the Desktop-style case: backend launched in
$HOME, workspace elsewhere, home-directory manual map present.

Refs #24740

(cherry picked from commit cfb32757de2509dd404acf98311e357d73fa741e)

plugins/memory/honcho/__init__.py

@@ -275,7 +275,11 @@ class HonchoMemoryProvider(DialecticMixin, MemoryProvider):
 
     def _resolve_session_key(self, cfg, session_id: str, **kwargs) -> str:
         """Resolve the Honcho session key without touching the network."""
+        from agent.runtime_cwd import resolve_agent_cwd
+
+        cwd = kwargs.get("cwd") or str(resolve_agent_cwd())
         return cfg.resolve_session_name(
+            cwd=cwd,
             session_title=kwargs.get("session_title"), session_id=session_id,
             session_title_source=kwargs.get("session_title_source"),
             gateway_session_key=kwargs.get("gateway_session_key"),