v2 Standard: Multiline String API for Triggers

[DerekRoberts]

Summary

We have officially decided to move from the heritage 'Bash-Array' syntax ('...' '...') to a standard Multiline String API for all trigger inputs in the consolidated re-launch.

Why Multiline String?

1. Maximum Predictability: GitHub preserves newlines exactly, ensuring we never have to guess how the string was constructed.
2. Backend Simplicity: We can parse this using a simple while read -r loop in Bash, eliminating fragile grep patterns.
3. Approachability: It is the standard way to handle lists in many other actions (like paths-filter).

Example Action v2:

with:
  triggers: |
    ./src/
    ./tests/
    ./Containerfile