Gemini CLI's templateString() treats all ${word} patterns in agent
system prompts as template variables, throwing "Template validation
failed: Missing required input parameters: PHASE" when GSD agents
contain shell variables like ${PHASE} in bash code blocks.
Convert ${VAR} to $VAR in agent bodies during Gemini installation.
Both forms are equivalent bash; $VAR is invisible to Gemini's
/\$\{(\w+)\}/g template regex. Complex expansions like ${VAR:-default}
are preserved since they don't match the word-only pattern.
Closes#613
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
e449c5afa6