fix(sessions): /save lands under $HERMES_HOME, widen browse+TUI picker, force-refresh ollama-cloud on setup (#16296)

Four independent session-UX bugs reported by an external user (#16294).

/save wrote hermes_conversation_<ts>.json to CWD — invisible to
'hermes sessions browse' and easy to lose. Snapshots now write under
~/.hermes/sessions/saved/ and the command prints the absolute path plus
a 'hermes --resume <id>' hint for the live DB-indexed session.

'hermes sessions browse' default --limit raised from 50 to 500. With the
old ceiling, users with moderately long histories saw only the most
recent 50 rows and assumed older sessions had been lost.

TUI session.list (`/resume` picker) switched from a hardcoded allow-list
of 13 gateway source names to a deny-list of just { 'tool' }. Sessions
tagged acp / webhook / user-defined HERMES_SESSION_SOURCE values and
any newly-added platform now surface. Default limit 20 → 200.

ollama-cloud provider setup passes force_refresh=True to
fetch_ollama_cloud_models() so a user entering their API key sees the
fresh catalog (e.g. deepseek v4 flash, kimi k2.6) immediately instead
of waiting up to an hour for the disk cache TTL to expire.

Closes #16294.

tests/hermes_cli/test_session_browse.py

@@ -401,14 +401,21 @@ class TestSessionBrowseArgparse:
         from hermes_cli.main import _session_browse_picker
         assert callable(_session_browse_picker)
 
-    def test_browse_default_limit_is_50(self):
-        """The default --limit for browse should be 50."""
-        # This test verifies at the argparse level
-        # We test by running the parse on "sessions browse" args
-        # Since we can't easily extract the subparser, verify via the
-        # _session_browse_picker accepting large lists
-        sessions = _make_sessions(50)
-        assert len(sessions) == 50
+    def test_browse_default_limit_is_500(self):
+        """The default --limit for browse should be 500."""
+        # Build the same argparse tree cmd_sessions uses and verify the default.
+        import argparse
+        parser = argparse.ArgumentParser()
+        subparsers = parser.add_subparsers(dest="sessions_action")
+        browse = subparsers.add_parser("browse")
+        browse.add_argument("--source")
+        browse.add_argument("--limit", type=int, default=500)
+
+        args = parser.parse_args(["browse"])
+        assert args.limit == 500
+
+        args = parser.parse_args(["browse", "--limit", "42"])
+        assert args.limit == 42
 
 
 # ─── Integration: cmd_sessions browse action ────────────────────────────────