skills: add install.fish for symlink setup

skills/install.fish

@@ -0,0 +1,38 @@
+#!/usr/bin/env fish
+# install.fish — Create symlinks from ~/.hermes/skills/ to ./skills/
+# Run from the skills/ directory or set SKILLS_DIR.
+
+set -q SKILLS_DIR; or set SKILLS_DIR (realpath (dirname (status filename)))
+set HERMES_SKILLS "$HOME/.hermes/skills"
+
+# skill name → category subdirectory under ~/.hermes/skills/
+set -l names \
+    pptx-translate \
+    chinese-text-normalize \
+    translation-review \
+    dharma-translation
+set -l cats \
+    productivity \
+    productivity \
+    productivity \
+    research
+
+for i in (seq (count $names))
+    set name $names[$i]
+    set cat  $cats[$i]
+    set src  "$SKILLS_DIR/$name"
+    set dst  "$HERMES_SKILLS/$cat/$name"
+
+    if not test -d "$src"
+        echo "SKIP: source not found: $src"
+        continue
+    end
+
+    if test -e "$dst" -o -L "$dst"
+        rm -rf "$dst"
+    end
+
+    mkdir -p (dirname "$dst")
+    ln -s "$src" "$dst"
+    echo "LINKED: $dst -> $src"
+end