fix(desktop,tui-gateway,zai): stop thinking-off from reverting to medium

A Z.ai desktop user reported thinking reverting to medium after one turn,
burning ~200% of a week's credits in 4 days despite reasoning_effort: false
in config.yaml. Four compounding bugs:

- _session_info reported reasoning_effort "" for disabled reasoning,
  indistinguishable from unset — the desktop adopted it after the first
  turn, wiping its sticky "thinking off" pick so every later chat
  reverted to the default effort.
- config.set key=reasoning always wrote agent.reasoning_effort to global
  config.yaml, so every desktop model-menu selection (preset.effort ??
  'medium') clobbered the user's configured value. Now session-scoped
  like the messaging gateway's /reasoning, landing on
  create_reasoning_override so lazily-built sessions keep it too.
- YAML `reasoning_effort: false`/`off`/`no` (boolean False) was coerced
  to "" by every loader's `str(x or "")`, silently re-enabling thinking.
  parse_reasoning_effort now treats False/"false"/"disabled" as
  {"enabled": False}; loaders (tui gateway, gateway, cli, cron,
  delegate) pass the raw value through. The desktop config reader also
  crashed on the boolean (false.trim()), aborting voice/STT settings.
- The zai provider profile never sent thinking on the wire, and GLM-4.5+
  defaults to thinking ON server-side — so disabling reasoning was a
  silent no-op on direct Z.ai, the actual token burner. The profile now
  emits extra_body.thinking {"type": "enabled"|"disabled"} for
  thinking-capable GLM models, mirroring the DeepSeek profile.

Also: /new (session reset) now carries reasoning_config across the
rebuild like model_override; config.get reasoning prefers the session's
live value and maps a config False to "none"; Settings shows "Off"
instead of a blank select for hand-written false.

plugins/model-providers/zai/__init__.py

@@ -1,9 +1,67 @@
-"""ZAI / GLM provider profile."""
+"""ZAI / GLM provider profile.
+
+Z.AI's GLM-4.5-and-later chat models default to thinking-mode ON when the
+request omits ``thinking``.  Hermes' ``reasoning_config = {"enabled": False}``
+was previously a silent no-op on this route — the base profile emits nothing,
+so users who turned thinking off (desktop toggle, ``/reasoning none``,
+``reasoning_effort: none``/``false`` in config.yaml) kept burning thinking
+tokens on every turn.
+
+:meth:`ZaiProfile.build_api_kwargs_extras` translates the Hermes reasoning
+config into the wire shape Z.AI's OpenAI-compat endpoint expects:
+
+    {"extra_body": {"thinking": {"type": "enabled" | "disabled"}}}
+
+When no reasoning preference is set (``reasoning_config is None``) the field
+is omitted so the server default applies, matching prior behavior.  GLM
+models before 4.5 (e.g. ``glm-4-9b``) don't accept ``thinking`` and are left
+untouched.
+"""
+
+from __future__ import annotations
+
+import re
+from typing import Any
 
 from providers import register_provider
 from providers.base import ProviderProfile
 
-zai = ProviderProfile(
+_GLM_VERSION_RE = re.compile(r"^glm-(\d+)(?:\.(\d+))?")
+
+
+def _model_supports_thinking(model: str | None) -> bool:
+    """GLM thinking-capable model families: glm-4.5 and later (4.5, 4.6, 5…)."""
+    m = (model or "").strip().lower()
+    match = _GLM_VERSION_RE.match(m)
+    if not match:
+        return False
+    major = int(match.group(1))
+    minor = int(match.group(2) or 0)
+    return (major, minor) >= (4, 5)
+
+
+class ZaiProfile(ProviderProfile):
+    """Z.AI / GLM — extra_body.thinking enabled/disabled."""
+
+    def build_api_kwargs_extras(
+        self, *, reasoning_config: dict | None = None, model: str | None = None, **context
+    ) -> tuple[dict[str, Any], dict[str, Any]]:
+        extra_body: dict[str, Any] = {}
+        top_level: dict[str, Any] = {}
+
+        if not _model_supports_thinking(model):
+            return extra_body, top_level
+
+        # Only emit when the user expressed a preference; omitting the field
+        # keeps the server default (enabled) exactly as before.
+        if isinstance(reasoning_config, dict):
+            enabled = reasoning_config.get("enabled") is not False
+            extra_body["thinking"] = {"type": "enabled" if enabled else "disabled"}
+
+        return extra_body, top_level
+
+
+zai = ZaiProfile(
     name="zai",
     aliases=("glm", "z-ai", "z.ai", "zhipu"),
     env_vars=("GLM_API_KEY", "ZAI_API_KEY", "Z_AI_API_KEY"),