Audit: long nested SNIP-12 key paths hide the signed values on the approval card (Sherlock 257) #585

Tracking issue for Sherlock #257 (Low/Info) and Sherlock #187 (Low/Info), targeted at v0.10.6.

• 257: the sign card composes one SNIP-12 name per nesting level into an unbounded dotted key, laid out at full width (flex: none). An ordinary nested order shows its signed recipient, amount and nonce at zero visible pixels while Sign is offered.
• 187: an unbounded domain name pushes the approval summary over the panel's 300-character limit, so the approval is dropped and the site's request hangs with nothing on screen.

Fix: let the key wrap, keep half the row for the value, withhold Sign past a key-length bound, and cut the summary's names at 64 characters.