fix: only deactivate on a standalone "stop ponytail" / "normal mode" (#162)

The deactivation check matched the phrase anywhere in the prompt, so an
ordinary request like "add a normal mode toggle" silently turned ponytail
off for the rest of the session. Match the whole message instead (trimmed,
case-insensitive, trailing punctuation ignored) through a shared helper used
by both the Claude/Codex hook and the pi extension.

Fixes #161

hooks/ponytail-mode-tracker.js

@@ -2,7 +2,7 @@
 // ponytail — UserPromptSubmit hook to track which ponytail mode is active
 // Inspects user input for /ponytail commands and writes mode to flag file
 
-const { getDefaultMode } = require('./ponytail-config');
+const { getDefaultMode, isDeactivationCommand } = require('./ponytail-config');
 const { clearMode, setMode, writeHookOutput } = require('./ponytail-runtime');
 
 let input = '';
@@ -45,7 +45,7 @@ process.stdin.on('end', () => {
     }
 
     // Detect deactivation
-    if (/\b(stop ponytail|normal mode)\b/i.test(prompt)) {
+    if (isDeactivationCommand(prompt)) {
       clearMode();
       writeHookOutput('UserPromptSubmit', 'off', 'PONYTAIL MODE OFF');
     }