fix(gemini): drop integer/number/boolean enums from tool schemas (#15082)

Gemini's Schema validator requires every `enum` entry to be a string,
even when the parent `type` is integer/number/boolean. Discord's
`auto_archive_duration` parameter (`type: integer, enum: [60, 1440,
4320, 10080]`) tripped this on every request that shipped the full
tool catalog to generativelanguage.googleapis.com, surfacing as
`Gateway: Non-retryable client error: Gemini HTTP 400 (INVALID_ARGUMENT)
Invalid value ... (TYPE_STRING), 60` and aborting the turn.

Sanitize by dropping the `enum` key when the declared type is numeric
or boolean and any entry is non-string. The `type` and `description`
survive, so the model still knows the allowed values; the tool handler
keeps its own runtime validation. Other providers (OpenAI,
OpenRouter, Anthropic) are unaffected — the sanitizer only runs for
native Gemini / cloudcode adapters.

Reported by @selfhostedsoul on Discord with hermes debug share.

agent/gemini_schema.py

@@ -73,6 +73,20 @@ def sanitize_gemini_schema(schema: Any) -> Dict[str, Any]:
             ]
             continue
         cleaned[key] = value
+
+    # Gemini's Schema validator requires every ``enum`` entry to be a string,
+    # even when the parent ``type`` is ``integer`` / ``number`` / ``boolean``.
+    # OpenAI / OpenRouter / Anthropic accept typed enums (e.g. Discord's
+    # ``auto_archive_duration: {type: integer, enum: [60, 1440, 4320, 10080]}``),
+    # so we only drop the ``enum`` when it would collide with Gemini's rule.
+    # Keeping ``type: integer`` plus the human-readable description gives the
+    # model enough guidance; the tool handler still validates the value.
+    enum_val = cleaned.get("enum")
+    type_val = cleaned.get("type")
+    if isinstance(enum_val, list) and type_val in {"integer", "number", "boolean"}:
+        if any(not isinstance(item, str) for item in enum_val):
+            cleaned.pop("enum", None)
+
     return cleaned