AI placeholder templates must replace repeated tokens

Problem

replacePlaceholders(...) looked fine for one-off template tokens, but repeated placeholders were only replaced once.

That meant prompts like Prompt: {prompt}\nAgain: {prompt} or templates with repeated {editor}-style tokens could silently ship partially expanded text to the AI layer.

Root Cause

The helper used String.prototype.replace(...), which only replaces the first occurrence of a string token.

That was enough for happy-path tests, but it lied for real templates that reused the same placeholder more than once.

Solution

Replace placeholders across the whole string instead of once:

let result = text.split('{prompt}').join(prompt || '');

result = result.split(placeholder).join(getMarkdown(editor, { type }));

Using split(...).join(...) keeps the logic simple and replaces every occurrence without regex escaping games.

Prevention

• Any template helper gets one repeated-token test. No exceptions.
• Do not trust single-occurrence placeholder tests; they miss the most boring bug in the book.
• When placeholder values come from other helpers, keep those tests real instead of mocking the substitution path.