driver: ignore wrong-suffix files as named sources

docs/spec.md

@@ -395,6 +395,52 @@ ImportPath    = ident { "." ident } .
   persistence, process, or filesystem owner. Build and all test forms retain
   their distinct stat-first directory behavior. Build workdir format remains
   18, test workdir format remains 19, and semantic storage format remains 3.
+- A public operand is eligible for direct named-source adoption only when its
+  exact requested spelling ends `.ww` and that command's existing file-kind
+  rule admits it. An existing non-directory object with another suffix is not
+  source: its bytes, package clause, imports, syntax, test declarations,
+  runtime behavior, mode, and timestamp are not read as source, and ordinary
+  dotted resolution continues exactly as though the colliding object were
+  absent. Thus request `foo.bar` may resolve `foo/bar.ww` or `foo/bar/` even
+  while a physical non-directory `foo.bar` exists. A wrong-suffix symlink to a
+  non-directory is the same ignored collision; a symlink to a directory remains
+  an ordinary stat-first directory request. A visible `.ww` symlink to a
+  regular source remains eligible, and the established stage-specific handling
+  of visible `.ww` special files is not broadened by this rule.
+
+  A resolved logical single file retains the established `__root` command-line
+  package/action/artifact identity. A resolved logical directory retains its
+  dotted package, import, graph, action, symbol, `.wwi`, initializer, artifact,
+  publication, and persistence identity. The ignored physical pathname/object
+  creates no membership, binding, edge, action, key, or alternate identity.
+  Build and run use only the logical provider's production/import/initializer
+  closure and runtime. Raw running test, its historical second-positional
+  test-name filter, `test -c`, and `test -S` use only the provider's test
+  package, descriptors, support closure, binary, and assembly.
+
+  When no provider exists, collision-present behavior is byte-for-byte the
+  existing collision-absent behavior. An ordinary single target retains its
+  direct build/run/test cannot-find result and creates no producer action. A
+  second positional retains the established package-coordinator route,
+  diagnostics, status, selection lifecycle, and cleanup; this source gate does
+  not reinterpret that positional form. Mutation invariance covers only absent
+  and stat-successful non-directory collision states. A transition to a
+  directory leaves this rule and follows ordinary directory routing, with no
+  new atomic-snapshot guarantee for concurrent kind changes.
+
+  Provider compilation failure preserves the prior public and semantic
+  generation. A retained running-test runtime failure occurs after the complete
+  logical build generation commits: it preserves prior retained public bytes by
+  skipping deferred installation, while that semantic generation remains
+  committed and reusable. Restoring prior source bytes requires a later
+  successful rebuild and commit, not runtime-failure rollback. Controlled-
+  failure cleanup otherwise remains unchanged. External signal
+  interruption after action start is unchanged, including the verified-open
+  fixed `.new` residue and later persistent-request poisoning. Multiple named
+  sources, remaining suffix-first run behavior, finite `.ww` FIFOs, test
+  process topology, and `-run` regular expressions are not completed here.
+  Build workdir format remains 18, test workdir format remains 19, and semantic
+  storage format remains 3.
 - `import acme.codec;` loads the canonical package `acme.codec`. If that
   package declares `package wire;`, the importing file sees its exported names
   as `wire.Name`; `codec.Name` is not an additional binding. An explicit alias