feat(shader): Add prepare_global_blur and high-DPI scaling support

- Add prepare_global_blur() method combining Deep Sea render + blur
- Add fb_scale parameter to setup_fbos() for high-DPI display support
- FBOs now created at scaled resolution (width * fb_scale, height * fb_scale)
- prepare_global_blur() auto-initializes FBOs if scale changes
- Add test_blur_pipeline_prepare_global_blur
- Add test_blur_pipeline_high_dpi_scaling

Task: Phase 2, Tasks 1-2 of frosted_glass_20260313 track

config.toml

@@ -23,15 +23,15 @@ active = "C:/projects/gencpp/gencpp_sloppy.toml"
 separate_message_panel = false
 separate_response_panel = false
 separate_tool_calls_panel = false
-bg_shader_enabled = true
+bg_shader_enabled = false
 crt_filter_enabled = false
 separate_task_dag = false
-separate_usage_analytics = false
+separate_usage_analytics = true
 separate_tier1 = false
 separate_tier2 = false
 separate_tier3 = false
 separate_tier4 = false
-separate_external_tools = false
+separate_external_tools = true
 
 [gui.show_windows]
 "Context Hub" = true
@@ -39,7 +39,7 @@ separate_external_tools = false
 "AI Settings" = true
 "MMA Dashboard" = true
 "Task DAG" = false
-"Usage Analytics" = false
+"Usage Analytics" = true
 "Tier 1" = false
 "Tier 2" = false
 "Tier 3" = false
@@ -56,8 +56,8 @@ Response = true
 Theme = true
 "Log Management" = true
 Diagnostics = false
-"External Tools" = false
-"Shader Editor" = false
+"External Tools" = true
+"Shader Editor" = true
 
 [theme]
 palette = "Nord Dark"
@@ -65,7 +65,7 @@ font_path = "C:/projects/manual_slop/assets/fonts/MapleMono-Regular.ttf"
 font_size = 18.0
 scale = 1.0
 transparency = 0.5400000214576721
-child_transparency = 0.5899999737739563
+child_transparency = 1.0
 
 [mma]
 max_workers = 4