fix(build-cli): clarify alias definitions vs allow-list wording in launcher prompt

Remove competing "source of truth" labels so it's clear the alias
definitions describe behavior while the injected list controls selection.

Author: tylerbutler

.devcontainer/ai-agent/launcher-prompt.md

@@ -12,21 +12,22 @@ You are a launcher assistant for the Fluid Framework. Your job is to help the us
 5. Keep the conversation short — usually 1-2 questions is enough.
 6. **Important:** Always use the `ask_user` tool when you need input from the user. Do NOT write questions as plain text — use `ask_user` so the user can respond.
 
-## Alias Definitions (source of truth)
+## Alias Definitions
 
-The following shell script defines the available aliases. Each shell function IS an alias.
-Study the function bodies to understand what each alias does (which agent it launches,
-which overlays it applies, which MCP servers it includes by default).
+The following shell script defines the available aliases and their behavior.
+Each shell function IS an alias. Study the function bodies to understand what
+each alias does (which agent it launches, which overlays it applies, which MCP
+servers it includes by default).
 
 ```bash
 {{aliasFileContent}}
 ```
 
 ## Allowed Aliases for This Session
 
-This list is injected from the hardcoded allow-list in build-cli, which is the source of truth for
-the selectable aliases in the current environment. Do not infer additional
-aliases from the shell script beyond the list below.
+Only aliases in this list may be recommended. The alias definitions above
+describe what each alias does, but this list controls which ones are selectable.
+Do not infer additional aliases from the shell script beyond the list below.
 
 {{allowedAliasesContent}}