Validate both family and attribute for compound params

Tighten compound-param validation to require both a known family
prefix and a known attribute. Immediately caught two doc bugs:
z_comain -> z_domain typo, model%%filepath -> model_filepath.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: sbryngelson

docs/documentation/case.md

@@ -997,7 +997,7 @@ When ``cyl_coord = 'T'`` is set in 3D the following constraints must be met:
 
 - `z_domain%beg = 0`  sets the azimuthal starting point to 0
 
-- `z_comain%end = 2*math.pi` to set the azimuthal ending point to $2\pi$ (note, requires `import math` in the case file)
+- `z_domain%end = 2*math.pi` to set the azimuthal ending point to $2\pi$ (note, requires `import math` in the case file)
 
 When ``cyl_coord = 'T'`` is set in 2D the following constraints must be met:
 
@@ -1087,7 +1087,7 @@ This boundary condition can be used for subsonic inflow (`bc_[x,y,z]%[beg,end]`
 | 18   | 2D Varcircle            | 2     | Y      | Requires `[x,y]_centroid`, `radius`, and `thickness` |
 | 19   | 3D Varcircle            | 3     | Y      | Requires `[x,y,z]_centroid`, `length_z`, `radius`, and `thickness` |
 | 20   | 2D Taylor-Green Vortex  | 2     | N      | Requires `[x,y]_centroid`, `length_x`, `length_y`, `vel(1)`, and `vel(2)` |
-| 21   | Model                   | 2 & 3 | Y      | Imports a Model (STL/OBJ). Requires `model%%filepath`. |
+| 21   | Model                   | 2 & 3 | Y      | Imports a Model (STL/OBJ). Requires `model_filepath`. |
 
 The patch types supported by the MFC are listed in table [Patch Types](#patch-types).
 This includes types exclusive to one-, two-, and three-dimensional problems.

toolchain/mfc/lint_docs.py

@@ -130,13 +130,13 @@ def _is_valid_param(param: str, valid_params: set, sub_params: set) -> bool:
     if base in valid_params or base in sub_params:
         return True
 
-    # Check sub-param part after %
+    # Compound params (with %): validate both family prefix and attribute
     if "%" in param:
         sub = param.split("%")[-1]
-        if sub in sub_params:
-            return True
+        family_ok = any(p.startswith(base + "%") for p in valid_params)
+        return family_ok and sub in sub_params
 
-    # Family prefix check (only accept at a boundary to avoid prefix-typo matches)
+    # Simple params: family prefix check at structural boundaries
     if any(p.startswith(base + b) for b in ("(", "%", "_") for p in valid_params):
         return True