fix: rename gtr.fish to git-gtr.fish

CLAUDE.md

@@ -403,7 +403,7 @@ When adding new commands or flags, update all three completion files:
 
 - `completions/gtr.bash` (Bash)
 - `completions/_git-gtr` (Zsh)
-- `completions/gtr.fish` (Fish)
+- `completions/git-gtr.fish` (Fish)
 
 ### Git Version Compatibility
 

README.md

@@ -133,7 +133,7 @@ source ~/.zshrc
 **Fish:**
 
 ```bash
-ln -s /path/to/git-worktree-runner/completions/gtr.fish ~/.config/fish/completions/
+ln -s /path/to/git-worktree-runner/completions/git-gtr.fish ~/.config/fish/completions/
 ```
 
 ## Commands

completions/gtr.fish → completions/git-gtr.fish

@@ -5,7 +5,7 @@
 #
 # Installation:
 #   Symlink to fish's completions directory:
-#     ln -s /path/to/git-worktree-runner/completions/gtr.fish ~/.config/fish/completions/
+#     ln -s /path/to/git-worktree-runner/completions/git-gtr.fish ~/.config/fish/completions/
 #   Then reload fish:
 #     exec fish