test: prove canonical directory test products

docs/spec.md

@@ -251,10 +251,12 @@ ImportName    = ident .
 ImportPath    = ident { "." ident } .
 ```
 
-- Every source file begins with a package clause. A directory of eligible
-  `.ww` files sharing one declared package name compiles as one package. The
-  declared name need not equal the directory name or the final component of its
-  canonical import identity.
+- Every source file begins with a package clause. Within one semantic source
+  action, eligible `.ww` files share one declared package name. Ordinary
+  production and same-package test sources use `p`; external test sources may
+  use the related `p_test`, and the actions remain separate even though one
+  canonical directory owns their test product. The declared name need not equal
+  the directory name or the final component of its canonical import identity.
 - Directory source eligibility uses Go 1.26.5 filename suffix semantics for
   WW's fixed `linux/amd64` target. In the basename stem before the first dot, a
   final `_test` token is ignored for platform matching. A final known OS or
@@ -286,10 +288,12 @@ ImportPath    = ident { "." ident } .
   initialization. Repeated blank occurrences and blank plus default/explicit
   named occurrences of one path are valid; every named occurrence remains
   independently subject to duplicate-binding and unused checks.
-  The package dependency graph is the sorted, deduplicated union of the real
-  imports in all eligible files. Occurrences retain their owning file and
-  position, but equal canonical targets create one graph edge/package action.
-  Self-import is rejected.
+  Each semantic action's package dependency graph is the sorted, deduplicated
+  union of real imports in that action's eligible source set. Occurrences retain
+  their owning file and position, but equal canonical targets create one graph
+  edge. Test-only occurrences never enter ordinary production. Self-import is
+  rejected, except that toolchain-owned external-test self wiring is rebound to
+  the effective augmented package action after ordinary per-site validation.
 - An executable package is one declared `package main` and containing a
   `fn main`; path and directory spelling do not classify commands. An ordinary
   import of a package declared `main` is rejected, except for the toolchain's
@@ -606,13 +610,21 @@ the program. Two placements, following the Go `foo` / `foo_test` model:
 ```
 
 Production, production-plus-white-box-test, external black-box-test, test
-support, and generated test main are distinct package actions. Before a test
-function runs, the generated test product initializes its exact reachable
-variant graph dependency-first and once per canonical action. A white-box
-variant replaces the colocated production task rather than initializing both;
-an external variant depends on ordinary production. Imports, runtime lets, and
-init declarations found only in `*_test.ww` never enter an ordinary production
-build.
+support, recompiled-for-test dependencies, and generated test main are distinct
+package actions. One canonical selected directory owns one test product and one
+generated main, which imports every applicable same-package and external target
+and produces one binary/result. The external action's import of the package
+under test binds to the augmented white-box action when it exists; affected
+transitive importers are copied and rewired so ordinary and augmented package
+state do not coexist in the linked closure.
+
+Before a test function runs, the one generated product initializes its exact
+effective graph dependency-first and once per canonical action. Imports,
+runtime lets, and init declarations found only in `*_test.ww` never enter an
+ordinary production build. Test-only same-package, external-package, and valid
+mixed directories are accepted from their selected test files. A directory
+with no selected test file validates ordinary production but creates no test
+support, generated main, link, binary, result, or process.
 
 ---