Decide the default string-deobfuscation behavior (all vs. static-only opt-in)

[vee1e]

Debate from PR #1376 , prompted by #1176 (silent 'no' when stdout is redirected).

Context: the interactive deobfuscation prompt ("enable string deobfuscation? [y/N]") was removed; the default currently runs all string types, including deobfuscation (stack/tight/decoded), with the existing Go/Rust "may be inaccurate and take a long time" warnings.

Options on the table:

1. Default runs all strings (Go/Rust deobfuscation included, with warnings), current behavior.
2. Default runs static (+ language) only; deobfuscation is opt-in via --string-type stack tight decoded.
3. Something else (e.g. keep a prompt but improve its UX)

cc: @mr-tz @williballenthin