#6857: docs: clarify that /elevated on is an alias for ask

## Summary The slash-commands quick reference and system prompt didn't explicitly mention that `on` and `ask` are equivalent for `/elevated`. This caused confusion — users couldn't determine what `on` does without consulting the source code or the dedicated elevated.md doc. ## Changes - **docs/tools/slash-commands.md**: Add note that `on` is an alias for `ask` in the command list - **src/agents/system-prompt.ts**: Update the elevated explanation from "ask runs exec..." to "on/ask run exec..." ## Context Discovered while testing: asked what `/elevated on` does, and couldn't answer definitively because the system prompt only explained `ask` and `full`, not `on`. The source code shows: ```typescript export function resolveElevatedMode(level?: ElevatedLevel | null): ElevatedMode { if (!level || level === "off") return "off"; if (level === "full") return "full"; return "ask"; // "on" maps here } ``` ## Testing Verified source code behavior matches the documentation change. --- 🤖 *Built together with Claude. Fully tested, code reviewed and understood.*