Waveform viewer search: decide bit-pattern vs text search by the format, never by the query characters

A windowed waveform viewer sends value searches to a backend. For numeric formats, the query is turned into a bit pattern (with x/z/? wildcards) that the backend matches on raw values. A bug: the pattern conversion ran for every format, and any query made only of 0/1/x/z/?/. characters was treated as a bit pattern, even for text formats (instruction disassembly, alias names, enum, string, fixed point, epoch time). Queries like "x1" or "0" then found nothing, while the same search on a fully loaded row worked. The fix: classify by the display format. Only formats whose match is a whole-value exact compare (bin/hex/oct/dec/signed/float) use the bit-pattern path. Every other format uses the format's own text matcher with the same substring semantics as non-windowed rows. Test with a text-format query that looks like a bit pattern, on both the windowed and whole-signal paths.