fix(editor): restore correct SQL string color across all themes

[thomaswasle]

Problem

SQL string literals (single-quoted values like 'foo') were rendering in a barely-readable dark
red in the Monaco editor for all themes (most visible in Dracula).

Root cause: Monaco's built-in SQL tokenizer sets tokenPostfix: ".sql", which means the token type
for SQL strings is string.sql, not string. Monaco 0.55 does not reliably fall back from
string.sql to the generic string rule, so SQL strings received no color override and fell through
to the base theme's unmatched-token rendering — a dark red on dark backgrounds.

Fix

Added an explicit string.sql token rule to every bundled Monaco theme JSON, using the same color
already defined for the generic string rule. Also updated generateMonacoTheme() in themeUtils.ts
to inject string.sql / string.quote.sql rules for themes that don't have a JSON file (Tabularis
Dark, Tabularis Light, High Contrast).

Theme	String color
Dracula	#f1fa8c
Monokai	#e6db74
Nord	#a3be8c
GitHub Dark	#79b8ff
GitHub Light	#032f62
Night Owl	#addb67
One Dark Pro	#98c379
Solarized Dark/Light	#2aa198
Tomorrow Night Eighties	#99cc99

Testing

Open the SQL console, select any theme, and type a query with a single-quoted string literal — it
should render in the theme's string color instead of red.