Exact numeric search in waveform viewers: anchor the regex

Waveform viewers that convert a typed number (hex 5) into a binary regex and test it against each value string often forget to anchor it, so '5' (0101) also matches 0x15, 0x25 and so on. Anchor the generated pattern to the whole value (^...$) after zero-extending the query to the signal width, or sign-extending for signed formats, while leaving user-written regexes and wildcards unanchored so .*0101.* stays a substring search. Test it with a value whose low bits match but whose upper bits differ.