script/install: write every listed file the repo lacks

A listed file the repo lacks is now written whole, with no keep rule.
A prompts/NAME.md goes to docs/NAME.md unless the repo keeps it at
NAME.md, and any other file goes to its own path. A language's files
are skipped when git tracks no source file of that language.

A listed path git ignores now stops the script before it writes.

README bullets split into short sentences, and a false sentence about
template repos deleted.

Model: opus-5-5

script/install

@@ -24,8 +24,9 @@ PROMPTS_URL="https://git.eeqj.de/sneak/prompts"
 PROMPTS_API_URL="https://git.eeqj.de/api/v1/repos/sneak/prompts"
 PROMPTS_FIRST_COMMIT="af257bef63f162a681bddc80d9b941c47a44b748"
 
-# Paths in the prompts repo. A file the target repo does not carry is
-# skipped, except the two scripts, which every repo gets.
+# Paths in the prompts repo. Every repo gets each file, written whole if
+# the repo lacks it. A language's files are skipped when git tracks no
+# source file of that language.
 VENDORED_FILES="
 .dockerignore
 .editorconfig
@@ -58,15 +59,36 @@ fetch() {
         die "cannot fetch $1"
 }
 
-# local_path <path in prompts>: print where the target repo keeps the
-# file, or nothing if git does not track it there. A prompts/NAME.md
-# lands at docs/NAME.md or NAME.md.
+# file_applies <path in prompts>: fail if the file is for a language of
+# which git tracks no source file in the target repo.
+file_applies() {
+    case "$1" in
+        .golangci.yml | prompts/CODE_STYLEGUIDE_GO.md | \
+            prompts/GO_HTTP_SERVER_CONVENTIONS.md)
+            [ -n "$(git ls-files -- '*.go')" ]
+            ;;
+        prompts/CODE_STYLEGUIDE_JS.md)
+            [ -n "$(git ls-files -- '*.js' '*.mjs' '*.ts')" ]
+            ;;
+        prompts/CODE_STYLEGUIDE_PYTHON.md)
+            [ -n "$(git ls-files -- '*.py')" ]
+            ;;
+    esac
+}
+
+# local_path <path in prompts>: print where the file goes in the target
+# repo. A prompts/NAME.md stays at NAME.md if git tracks it there and not
+# at docs/NAME.md; otherwise it goes to docs/NAME.md. Any other file goes
+# to its own path.
 local_path() {
     name="${1#prompts/}"
-    if [ "$name" != "$1" ] && [ -n "$(git ls-files -- "docs/$name")" ]; then
-        echo "docs/$name"
-    elif [ -n "$(git ls-files -- "$name")" ]; then
+    if [ "$name" = "$1" ]; then
+        echo "$1"
+    elif [ -z "$(git ls-files -- "docs/$name")" ] &&
+        [ -n "$(git ls-files -- "$name")" ]; then
         echo "$name"
+    else
+        echo "docs/$name"
     fi
 }
 
@@ -177,9 +199,8 @@ $own"
 # stop_on_own_script <fetched> <local>: stop if the local script has a
 # line the canonical file has never held, unless it is blank or a
 # comment: the repo wrote that script itself, and replacing it would
-# delete it. A repo without the script is fine.
+# delete it.
 stop_on_own_script() {
-    [ -e "$2" ] || return 0
     own="$(local_only_lines "$1" "$2")"
     if [ -n "$own" ]; then
         die "$2 has lines the canonical file has never held; rename the repo's own script to keep it:
@@ -210,23 +231,24 @@ main() {
     fetch "$PROMPTS_URL/compare/$PROMPTS_FIRST_COMMIT...$commit.patch" \
         "$tmp/history.patch"
 
-    carried=""
+    to_write=""
     for file in $VENDORED_FILES; do
-        case "$file" in
-            script/*) path="$file" ;;
-            *) path="$(local_path "$file")" ;;
-        esac
-        [ -n "$path" ] || continue
+        file_applies "$file" || continue
+        path="$(local_path "$file")"
+        if git check-ignore -q -- "$path"; then
+            die "$path is ignored by git; stop ignoring it"
+        fi
         if [ -n "$(git status --porcelain -- "$path")" ]; then
             die "$path has uncommitted changes"
         fi
         mkdir -p "$tmp/$(dirname "$path")"
         fetch "$PROMPTS_URL/raw/commit/$commit/$file" "$tmp/$path"
         former_lines "$tmp/history.patch" "$file" > "$tmp/$path.former"
-        carried="$carried $path"
+        to_write="$to_write $path"
     done
 
-    for path in $carried; do
+    for path in $to_write; do
+        [ -e "$path" ] || continue
         case "$path" in
             .gitignore | .editorconfig | .dockerignore)
                 keep_lines_below_last "$tmp/$path" "$path"
@@ -241,12 +263,12 @@ main() {
     done
 
     echo "$commit"
-    for path in $carried; do
+    for path in $to_write; do
+        mkdir -p "$(dirname "$path")"
         case "$path" in
             script/*)
                 # A new name and mv, because script/update-policy may
                 # be the script running.
-                mkdir -p script
                 cp "$tmp/$path" "$path.new"
                 chmod 755 "$path.new"
                 mv "$path.new" "$path"