Fix OFX plugin render failures and stabilize integration tests

This commit resolves several categories of OFX plugin failures that
  manifested as magenta (pink) render output or crashes:

  1. Param default-value initialization
     - IntegerInstance, DoubleInstance, BooleanInstance, ChoiceInstance,
       and StringInstance now read kOfxParamPropDefault from the descriptor
       at construction time. Previously, when no PluginNode was attached
       (integration-test mode), get() returned 0/0.0/false, causing
       generator plugins to receive invalid extent/format/PAR values and
       crash in coordinate assertions.
     - IntegerInstance also fixed uninitialized `id` that caused
       kOfxStatErrBadHandle in CImg plugins.

  2. Clip property initialization
     - newClipInstance() now seeds pixelDepth and components from the
       host VideoParams instead of leaving them as None. This prevents
       Transform3x3Plugin and similar plugins from asserting on
       getPixelComponentCount() during fetchClip inside createInstance.
     - getAspectRatio() and getProjectPixelAspectRatio() now fall back
       to 1.0 when the project's PAR is not yet set, avoiding division-
       by-zero in coordinate conversion.

  3. Frame-rate and time-base preservation
     - setInputTexture() no longer overwrites the clip's frame_rate or
       time_base with the input texture's values. Multi-input plugins
       were crashing because setupClipPreferencesArgs throws when inputs
     have mismatched rates.

  4. Render loop hardening
     - getClipPreferences() is now wrapped in try/catch so that frame-
       rate mismatch exceptions mark render failure instead of aborting
       the render thread.
     - getRegionOfInterestAction() treats kOfxStatErrBadHandle as non-
       fatal and falls back to default RoI.
     - RenderPlugin syncs all clip instances after setVideoParam so that
       getAspectRatio/getFrameRate return valid values before
       createInstanceAction queries them.

  5. Test suite updates
     - All PluginMisc tests now use F32 input to match the host pipeline
       default.
     - CreateGradientTexture fixed to support F32 pixel format.
     - Added CImgBilateral and CImgGuided_MultiInput tests.
     - Secret parameters are now registered as hidden Node inputs so that
       getClipPreferences can read them (fixes generator pink screen).

  6. Debug logging in HostSupport
     - clipGetImage and clipGetRegionOfDefinition now catch exceptions
       and log the failing clip name for easier debugging.

app/pluginSupport/OliveClip.cpp

@@ -346,7 +346,11 @@ const std::string &olive::plugin::OliveClipInstance::getPremult() const
 }
 double olive::plugin::OliveClipInstance::getAspectRatio() const
 {
-	return params_.pixel_aspect_ratio().toDouble();
+	double par = params_.pixel_aspect_ratio().toDouble();
+	if (par == 0.0) {
+		return 1.0; // default PAR when not explicitly set
+	}
+	return par;
 }
 double olive::plugin::OliveClipInstance::getFrameRate() const
 {
@@ -569,7 +573,17 @@ void olive::plugin::OliveClipInstance::setInputTexture(TexturePtr texture, OfxTi
 	}
 	VideoParams incoming = texture->params();
 	
+	// Preserve time-related properties from the host/project.
+	// The frame rate of an OFX clip should reflect the project's frame rate,
+	// not the individual input texture's frame rate. If different inputs
+	// have different frame rates, setupClipPreferencesArgs throws an exception.
+	rational saved_frame_rate = params_.frame_rate();
+	rational saved_time_base = params_.time_base();
+	
 	this->params_ = incoming;
+	
+	params_.set_frame_rate(saved_frame_rate);
+	params_.set_time_base(saved_time_base);
 	// Note: We do NOT call setPixelDepth/setComponents here because
 	// those should be set by getClipPreferences to reflect the PLUGIN's
 	// preferred format, not the input texture's format.