[BUG] Score phrase system appends to defaults instead of replacing them and has defaults in templates

[safepay]

Problems

1. Custom phrases append to defaults instead of replacing them. Any phrases entered in the settings UI are concatenated onto the 15 hardcoded built-in phrases rather than overriding them.

2. Built-in defaults are hardcoded in JS, not Python. The 15 default phrases live only inside a PikaraokeConfig JavaScript object in splash.html. They are unreachable from Python and there is no single source of truth. preference_manager.py has empty strings as the defaults for all three phrase keys.

Solution

• Move the 15 built-in phrases into a Python helper function in splash.py (where Flask-Babel translation has request context), replacing the hardcoded JS block.
• Add a GET /splash/score_phrases JSON endpoint that returns translated built-ins when no custom phrases are configured, or the user's custom phrases otherwise (never translated).
• Have splash.js fetch from this endpoint at startup instead of reading the baked-in config object — enabling future live updates without a page refresh.
• Store custom phrases as |-separated strings in config.ini (cleaner than multi-line configparser values).
• Update the settings UI help text to make clear that filling the textboxes overrides the defaults; leaving them empty restores the defaults.