fix(hooks): use Python JSON generation for reliable context injection

- Replace bash escape_json + printf with Python json.dump for
  reliable handling of Unicode and special characters in SKILL.md
- Output follows superpowers pattern: hookSpecificOutput.additionalContext
- 55KB context, 1230 lines, 8 mandatory skills injected at session start
- Tested: JSON valid, content complete

hooks/hooks.json

@@ -3,15 +3,18 @@
     "SessionStart": [{
       "hooks": [{
         "type": "command",
-        "command": "bash \"$CLAUDE_PLUGIN_ROOT/hooks/scripts/detect-project.sh\"",
-        "timeout": 10
+        "command": "\"${CLAUDE_PLUGIN_ROOT}/hooks/scripts/detect-project.sh\"",
+        "shell": "bash",
+        "timeout": 10,
+        "async": false
       }]
     }],
     "PreToolUse": [{
       "matcher": "Write|Edit",
       "hooks": [{
         "type": "command",
-        "command": "bash \"$CLAUDE_PLUGIN_ROOT/hooks/scripts/detect-file-type.sh\" \"$TOOL_INPUT\"",
+        "command": "\"${CLAUDE_PLUGIN_ROOT}/hooks/scripts/detect-file-type.sh\" \"$TOOL_INPUT\"",
+        "shell": "bash",
         "timeout": 10
       }]
     }]