Fast cables no longer get short-changed by slower devices

WhatCable had the logic backwards on one thing: it treated the live Thunderbolt
link speed as the most a cable could do. It's actually a floor, not a ceiling.
Plug an 80 Gbps cable into a 40 Gbps drive and the cable now still reads
80 Gbps, with a separate line describing the live link, and Negotiation
Diagnostics points at the device as the limit. Thanks @cannotcollide for the
report (#393).

Fixed

• 80 Gbps cables no longer read as 40 Gbps when the device is the
  bottleneck. The negotiated link speed is now treated as proof of what the
  cable can carry, never as a cap on it. When the e-marker claims more than the
  current link uses, you'll see a "Thunderbolt link active at N Gbps" line
  about the connection instead of a wrong claim about the cable. Thanks
  @cannotcollide (#393).
• Device brands no longer doubled. A Thunderbolt device whose model name
  already includes its brand used to show up as "Ugreen Ugreen Storage
  Device". Now it's just the once. Thanks @ebondfrancisco (#392).
• Buttons respond across the whole button. The header buttons only
  registered clicks over the exact icon shape, so near-misses did nothing.
  The full button area is clickable now. Thanks @jckirton (#386).
• Port card titles no longer get squashed when the Pro "Track as...?"
  chip is showing.

Heads up

• Some cables' trust tier moves from green to amber. If your cable claims
  a speed nothing in your setup can actually test (an 80 Gbps cable where the
  Mac and every device top out at 40, say), it now shows amber, "not yet seen
  to perform at its claim", instead of green. The old green was circular: it
  trusted the very reading this release fixes. Plug the cable into hardware
  that can use its full speed and it earns the green properly.
• One conflict banner has gone quiet on purpose. A registered-brand cable
  claiming a speed tier nothing in the chain can test no longer gets a
  "conflicting speed" banner. Untestable is not evidence of lying. Cables with
  blanked-out vendor IDs are still flagged by the trust signals.

Improved

• Display Diagnostics now uses macOS's own DisplayPort link description
  instead of a number we derived ourselves, so the link-rate line always
  matches what the system believes.

Under the hood

• Test Kit hardening for contributors: long probe output no longer gets cut
  off mid-dump, probes that fail are reported instead of silently skipped, and
  two probes capture extra port-mapping data that helps us line up multi-port
  machines.
• More cables in the built-in database, several straight from community
  reports.
• A large batch of internal regression tests that replay real community
  diagnostic data through the parsers, so this class of bug is harder to
  reintroduce.