Stop the callback expression parser corrupting and dropping arguments

[sadiqk2]

The bug

CallbackRegistry::parse() converted argument literals to JSON with str_replace("'", '"'), which rewrites every apostrophe in the expression regardless of its role. Three distinct failures, none of which reports anything:

Expression	Result
save("don't")	arguments dropped — the apostrophe becomes a quote, the JSON is invalid
setName('O'Brien')	arguments dropped
rename('it\'s fine')	arguments corrupted to it"s fine

The third is the one worth being careful about: json_decode succeeds, so the handler runs — with a value the author never wrote. The first two invoke the handler with no arguments at all, which for something like save($draft) looks exactly like a call that worked.

The fix

The conversion now walks the string tracking which quote opened the current literal:

• an apostrophe inside a double-quoted literal is data and stays put;
• \' inside a single-quoted literal becomes a bare apostrophe, since JSON has no such escape;
• a double quote inside a single-quoted literal is escaped rather than rewritten.

An expression that still cannot be parsed keeps the existing contract — args => [], because callers spread the result and a null would be a TypeError — but it now says so via error_log instead of failing silently. Changing that contract felt like it belongs in its own change rather than a bug fix.

Verification

Six cases added to tests/Unit/Edge/CallbackRegistryTest.php: apostrophe in a double-quoted argument, escaped apostrophe in a single-quoted one, double quote inside a single-quoted one, the ordinary literals (int, string, bool, null, multiple args, no parens, empty parens), a comma inside a quoted argument, and the unparseable fallback.

Three fail against main. Full suite: 887 passed, with the 13 failures identical to main's baseline (Android splash-screen and release-build tests, unrelated). vendor/bin/pint clean.