fix: use Common Pipeline State API for cross-API compatibility in get_pipeline_state

[lou-gege]

Fix: get_pipeline_state returns incomplete data on OpenGL/Vulkan captures

Problem

get_pipeline_state only returned event_id, api, and shaders fields
on OpenGL/Vulkan captures. All other pipeline state (viewports, render targets,
depth target, input assembly) was silently lost.

Root cause: The code used D3D-specific methods (GetViewportScissor(),
GetOutputMerger(), GetIAState()) that don't exist in the Common Pipeline
State Abstraction. These calls threw exceptions on GL/VK, which were caught
by except Exception: pass and silently discarded.

Solution

Replaced all D3D-specific API calls with RenderDoc's Common Pipeline State
Abstraction (PipeState) methods that work across all graphics APIs:

Before (D3D-only)	After (Cross-API)
pipe.GetViewportScissor()	pipe.GetViewport(index)
pipe.GetOutputMerger().renderTargets	pipe.GetOutputTargets()
pipe.GetOutputMerger().depthTarget	pipe.GetDepthTarget()
pipe.GetIAState().topology	pipe.GetPrimitiveTopology()
except Exception: pass	except Exception as e: info["*_error"] = str(e)

Changes

• File: renderdoc_extension/services/pipeline_service.py (1 file, +41/-39)
• No new dependencies, no MCP protocol changes
• Return JSON structure is backward compatible (same field names)

Testing

Verified on real captures via MCP IPC:

Before fix (OpenGL): {"event_id": 204, "api": "GraphicsAPI.OpenGL"} — only 2 fields
After fix (OpenGL): all 7 fields returned (event_id, api, shaders, viewports, render_targets, depth_target, input_assembly)