fix(agent): consult supports_vision override in auto-mode routing

The contributor PR (#17936) only patched the strip path in
`_model_supports_vision()`. The auto-mode router in
`agent/image_routing._lookup_supports_vision` still only read models.dev,
so a custom-provider model declared as vision-capable would still get its
images routed through vision_analyze in the default `agent.image_input_mode:
auto` setting. Users had to set both `supports_vision: true` AND
`image_input_mode: native` to bypass the text pipeline.

Single-knob behavior now: `supports_vision: true` alone is enough in auto
mode. The strip path and the routing path consult the same resolver.

- Extract override resolution into `_supports_vision_override()` in
  agent/image_routing.py and wire it into `_lookup_supports_vision()`.
- Refactor `run_agent._model_supports_vision` to call the same helper
  (DRY, single source of truth for the resolution order).
- Strict YAML boolean coercion: `supports_vision: "false"` (quoted —
  a common YAML mistake) no longer coerces to True via bool() truthiness.
  Recognised tokens: true/false/yes/no/on/off/1/0 plus real bools and 0/1.
  Unrecognised values return None and fall through to models.dev.
- Add @CNSeniorious000 to AUTHOR_MAP for release attribution.

Tests: 26 new (TestCoerceCapabilityBool, TestSupportsVisionOverride,
TestLookupSupportsVisionOverride, TestAutoModeRespectsOverride). Existing
contributor tests + image_routing + vision_native_fast_path +
native_image_buffer_isolation all green (92/92).

agent/image_routing.py

@@ -46,6 +46,84 @@ logger = logging.getLogger(__name__)
 _VALID_MODES = frozenset({"auto", "native", "text"})
 
 
+# Strict YAML/JSON boolean coercion for capability overrides.
+#
+# ``bool("false")`` is True in Python because non-empty strings are truthy, so
+# a user writing ``supports_vision: "false"`` (quoted — a common YAML mistake)
+# would silently enable native vision routing on a model that can't actually
+# handle it. Accept only the values YAML 1.1 / 1.2 treat as booleans, plus
+# real ``bool`` and integer 0/1. Anything else returns None so the caller
+# falls through to models.dev rather than honouring garbage.
+_TRUE_TOKENS = frozenset({"true", "yes", "on", "1"})
+_FALSE_TOKENS = frozenset({"false", "no", "off", "0"})
+
+
+def _coerce_capability_bool(raw: Any) -> Optional[bool]:
+    """Return True/False for recognised boolean values, None otherwise."""
+    if isinstance(raw, bool):
+        return raw
+    if isinstance(raw, int):
+        if raw in (0, 1):
+            return bool(raw)
+        return None
+    if isinstance(raw, str):
+        s = raw.strip().lower()
+        if s in _TRUE_TOKENS:
+            return True
+        if s in _FALSE_TOKENS:
+            return False
+    return None
+
+
+def _supports_vision_override(
+    cfg: Optional[Dict[str, Any]],
+    provider: str,
+    model: str,
+) -> Optional[bool]:
+    """Resolve user-declared vision capability from config.yaml.
+
+    Resolution order, first hit wins:
+      1. ``model.supports_vision`` (top-level shortcut for the active model)
+      2. ``providers.<provider>.models.<model>.supports_vision``
+         (named custom providers — ``provider`` may be the runtime-resolved
+         value ``"custom"`` and/or the user-declared name under
+         ``model.provider``; both are tried)
+
+    Returns None when no override is set, so the caller falls through to
+    models.dev. Returns False explicitly only when the user wrote a
+    recognised boolean false token.
+    """
+    if not isinstance(cfg, dict):
+        return None
+
+    # 1. Top-level shortcut
+    model_cfg_raw = cfg.get("model")
+    model_cfg: Dict[str, Any] = model_cfg_raw if isinstance(model_cfg_raw, dict) else {}
+    top = _coerce_capability_bool(model_cfg.get("supports_vision"))
+    if top is not None:
+        return top
+
+    # 2. Per-provider, per-model. Named custom providers (e.g. "my-vllm")
+    # get rewritten to provider="custom" at runtime
+    # (hermes_cli/runtime_provider.py:_resolve_named_custom_runtime), so the
+    # config still holds the user-declared name under model.provider. Try
+    # both as candidate provider keys.
+    config_provider = str(model_cfg.get("provider") or "").strip()
+    providers_raw = cfg.get("providers")
+    providers_cfg: Dict[str, Any] = providers_raw if isinstance(providers_raw, dict) else {}
+    for p in dict.fromkeys(filter(None, (provider, config_provider))):
+        entry_raw = providers_cfg.get(p)
+        entry: Dict[str, Any] = entry_raw if isinstance(entry_raw, dict) else {}
+        models_raw = entry.get("models")
+        models_cfg: Dict[str, Any] = models_raw if isinstance(models_raw, dict) else {}
+        per_model_raw = models_cfg.get(model)
+        per_model: Dict[str, Any] = per_model_raw if isinstance(per_model_raw, dict) else {}
+        coerced = _coerce_capability_bool(per_model.get("supports_vision"))
+        if coerced is not None:
+            return coerced
+    return None
+
+
 def _coerce_mode(raw: Any) -> str:
     """Normalize a config value into one of the valid modes."""
     if not isinstance(raw, str):
@@ -81,8 +159,20 @@ def _explicit_aux_vision_override(cfg: Optional[Dict[str, Any]]) -> bool:
     return True
 
 
-def _lookup_supports_vision(provider: str, model: str) -> Optional[bool]:
-    """Return True/False if we can resolve caps, None if unknown."""
+def _lookup_supports_vision(
+    provider: str,
+    model: str,
+    cfg: Optional[Dict[str, Any]] = None,
+) -> Optional[bool]:
+    """Return True/False if we can resolve caps, None if unknown.
+
+    Consults the user's ``supports_vision`` override in config.yaml first
+    (so custom/local models declared as vision-capable don't fall through to
+    text routing in ``auto`` mode), then falls back to models.dev.
+    """
+    override = _supports_vision_override(cfg, provider, model)
+    if override is not None:
+        return override
     if not provider or not model:
         return None
     try:
@@ -123,7 +213,7 @@ def decide_image_input_mode(
     if _explicit_aux_vision_override(cfg):
         return "text"
 
-    supports = _lookup_supports_vision(provider, model)
+    supports = _lookup_supports_vision(provider, model, cfg)
     if supports is True:
         return "native"
     return "text"