feat(render): SAGE water/ocean shaders, per-user logs, camera & culling

Terrain pass now ports the SAGE water model (Ocean.fx / OpenSAGE Water.frag): a de-gridded procedural wave normal combined with the retail ra3_deepocean flow and ra3_deepocean_nrm bump maps (appended as the last two terrain-atlas layers, no new backend binding), Schlick fresnel, sky reflection + depth-graded refraction, SAGE diffuse/specular lighting, depth-based transparency, and an underwater tint (UnderwaterDeferred.fx). Mirrored across terrain.frag / dx_terrain.hlsl / webgl_terrain_frag.glsl / webgpu_terrain.wgsl.

Also: logs move to the per-user state dir (%LOCALAPPDATA%\\OpenRA3\\logs, else XDG) and archive as openra3.<stamp>.log; the FPS label shows the active backend; middle-drag camera reset; objects and roads below the water plane are culled.

docs/ARCHITECTURE.md

@@ -533,7 +533,8 @@ Mirrors SAGE `GameEngine/Common`. Everything else speaks this.
   - `[ ]` pass scheduling, barriers, transient/aliased resources `(v0.6)`
 - **F3 Terrain render** `[~]`
   - `[x]` top-down software + GPU heightfield with blend ramp + gutter atlas
-  - `[ ]` perspective terrain mesh, LOD, cliff, water `(v0.6)`
+  - `[ ]` perspective terrain mesh, LOD, cliff `(v0.6)`
+  - `[x]` water surface in the raymarch: SAGE `Water.frag` port (ocean/river) `[~]`
 - **F4 Model render** `[~]`
   - `[x]` static map-object triangle soup, world-space, depth-tested over the terrain (Vulkan + software)
   - `[x]` bind-pose skinning (bone-space vertices) + ground-decal depth bias
@@ -550,8 +551,35 @@ Mirrors SAGE `GameEngine/Common`. Everything else speaks this.
   - `[x]` ARGB framebuffer, blit/line/circle/text, TGA decode, BMP encode
   - `[x]` map compositing, grid, markers; headless output
 - **F9 Post-processing** `[ ]`
+  - `[x]` underwater tint/fog in the terrain pass (retail `UnderwaterDeferred.fx`) `[~]`
   - `[ ]` bloom, color grading, AA, resolution scaling `(v0.7)`
 
+### M16b shader porting status (retail `Data\Shaders.big` → `*.fxo`)
+
+The retail set is **88 compiled effects** (`Core12\shaders\compiled`, duplicated
+in `Misc`/`Shaders`; `Core5`/`Core8` ship only `terrain`; plus a 60-byte
+`null` stub). OpenRA3 implements the static-map subset only:
+
+- **Ported (approximate stand-ins, shared by all backends):** `Terrain.fx`
+  (`terrain.*`), the opaque diffuse subset of `BuildingsGeneric.fx` /
+  `BasicW3D.fx` / `ObjectsGeneric.fx` (`object.*`), and the SAGE water model
+  `Ocean.fx` (+ `OceanDisplacement`/`OceanNoVertexTexture`/`RiverWater`/
+  `RiverReflection`/`UnderwaterDeferred`, folded into the `terrain.*` water
+  branch — see `docs/REVERSE_ENGINEERING.md`). The retail water flow and bump
+  maps (`art/terrain/ra3_deepocean.tga`, `ra3_deepocean_nrm.tga`) ride as the
+  last two terrain-atlas layers, so no backend adds a binding.
+- **Not ported:** all faction/variant model shaders (`buildings*`, `objects*`,
+  `basicw3d*`, `defaultw3d*`, `normalmapped`, `tree`/`treesway`), instances/
+  animation (`infantry*`), particles and beams (`cpuparticle`, `gpuparticle*`,
+  `swarmparticle`, `laser*`, `lightning`, `fx*`, `tracer`, `trail`,
+  `connectionline`, `linerenderers`, `stream`, `rain`, `simple*`), shadows and
+  ground decals (`shadow`, `decal`, `outlines`, `occlusion`, `terraintracks`),
+  post-processing (`postfx_*`), and the 2D/misc shaders (`render2d`, `video`,
+  `bootupscreen`, `debug`, `errormissing`, `rotateenvironmentmap`,
+  `distortingobject`). The shared retail includes `shadowmap.fxh`, `ssao.fxh`,
+  `macrotexture.fxh`, `gamma.fxh` are likewise absent (`skinning.fxh` is done at
+  bind pose only).
+
 ### M17 `ra3.ui` — platform layer & backends `[D]`
 
 - **F1 Display abstraction** `[D]`