Move render target clear mapping to renderer gl

docs/modernization/build-inventory.md

@@ -127,8 +127,9 @@ Known local toolchain state:
   by the legacy app initialization path; `pp_renderer_gl_capabilities_tests`
   validates framebuffer fetch, map-buffer alignment, desktop GL float support,
   GLES float/half-float extensions, WebGL exclusion behavior, and the
-  upload-type mapping used by legacy `Texture2D` and `RTT` creation. It also
-  validates image channel-count to OpenGL texture format mapping, including
+  upload-type mapping used by legacy `Texture2D` and `RTT` creation, plus the
+  RGBA pixel-format mapping used by `RTT` texture allocation. It also validates
+  image channel-count to OpenGL texture format mapping, including
   invalid channel counts rejected by `Texture2D::create(Image)`, RGBA8/RGBA32F
   readback formats, byte-count math, and PBO pixel-buffer target/usage/access
   mapping used by `RTT` and `PBO` readbacks, and framebuffer status naming
@@ -137,7 +138,9 @@ Known local toolchain state:
   `RTT::resize` and `RTT::copy`, plus the default linear clamp-to-edge
   render-target texture parameters, texture/renderbuffer targets, depth format,
   framebuffer targets, binding queries, attachment points, and completion
-  status used by `RTT::create` and framebuffer bind/restore paths. It also
+  status used by `RTT::create` and framebuffer bind/restore paths, plus RTT
+  clear color/depth masks and color-write-mask query tokens. `RTT` no longer
+  spells GL enum names directly. It also
   validates Shape index-type and fill/stroke primitive-mode mapping used by the
   legacy mesh draw path, plus the PanoPainter cube-face to OpenGL texture-target
   mapping used by `TextureCube`.

docs/modernization/roadmap.md

@@ -388,7 +388,8 @@ catalog now consumed by the legacy OpenGL app initialization path.
 `pp_renderer_gl` now exists as the first OpenGL backend library and owns pure
 OpenGL capability detection for framebuffer fetch, map-buffer alignment, and
 float texture support. It also owns the OpenGL texture upload-type mapping used
-by legacy `Texture2D` and `RTT` creation, plus image channel-count to texture
+by legacy `Texture2D` and `RTT` creation, RGBA pixel-format mapping used by
+`RTT` texture allocation, plus image channel-count to texture
 format mapping for `Texture2D` image uploads and framebuffer status naming for
 `RTT` diagnostics. RGBA8/RGBA32F readback formats, byte-count math, and PBO
 pixel-buffer target/usage/access tokens used by `RTT` and `PBO` readbacks now
@@ -397,14 +398,15 @@ filter tokens used by `RTT::resize` and `RTT::copy`, plus the default
 render-target texture parameters, texture/renderbuffer targets, depth format,
 framebuffer targets, binding queries, attachment points, and completion status
 used by `RTT::create` and framebuffer bind/restore paths, also live in
-`pp_renderer_gl`.
+`pp_renderer_gl`. RTT clear color/depth masks and color-write-mask query tokens
+also live in `pp_renderer_gl`. `RTT` no longer spells GL enum names directly.
 Mesh index-type and primitive-mode
 decisions used by legacy `Shape` drawing and the PanoPainter cube-face to
 OpenGL texture-target mapping used by `TextureCube` also live in
 `pp_renderer_gl`. The legacy app delegates extension, upload-format,
-framebuffer diagnostic, framebuffer blit, render-target setup, mesh draw-mode,
-and cube-face texture-target interpretation to that backend library. Sampler
-wrap, min/mag filter, and desktop border-color parameter
+framebuffer diagnostic, framebuffer blit, render-target setup, clear-state,
+mesh draw-mode, and cube-face texture-target interpretation to that backend
+library. Sampler wrap, min/mag filter, and desktop border-color parameter
 mapping for legacy `Sampler` also lives in `pp_renderer_gl`. The PanoPainter shader attribute
 binding catalog also lives in `pp_renderer_gl` and is consumed by legacy
 `Shader` creation. Shader uniform hashing, catalog validation, active-uniform