Rename script/fetch-policy to script/commit-current-upstream-policy-docs

sneak, on the PR: the script does more than fetch, and short names are
not wanted. The make target, the test names, the variables and the
messages take the new name. Behaviour is unchanged.

Model: opus-5-5

TODO.md

@@ -21,11 +21,12 @@ fmt-check, and commit.
 
 # Completed Steps
 
-- 2026-11-09: `script/fetch-policy` writes the vendored policy files into a repo
-  over HTTP, itself and `script/update-policy` among them
-  (https://git.eeqj.de/sneak/prompts/issues/165). `make update-policy` now
-  fetches the current `script/fetch-policy`, runs it and commits without
-  pushing. The template repositories get both scripts in their own issues.
+- 2026-11-09: `script/commit-current-upstream-policy-docs` writes the vendored
+  policy files into a repo over HTTP, itself and `script/update-policy` among
+  them (https://git.eeqj.de/sneak/prompts/issues/165). `make update-policy` now
+  fetches the current `script/commit-current-upstream-policy-docs`, runs it and
+  commits without pushing. The template repositories get both scripts in their
+  own issues.
 - 2026-11-09: `script/update-policy` and `make update-policy` update a repo's
   vendored policy files with one command
   (https://git.eeqj.de/sneak/prompts/issues/162). They fetch the files from