docs: add a laptop feedback path — issue template and an end-of-page 'give feedback' call

[mrsabath]

Feature Description

The laptop docs explain how to install Cortex and how to read the numbers, but they do not give a
first-time user an obvious way to tell us what worked and what did not. Today the Slack and issue
links sit at the end of pages under "related", so the likely outcome is a silent install: the user
tries it, forms an impression, and we never hear it.

This backs exit criterion 5 of the v0.9.0 release (#962):
a new user self-serves from the docs and can then say what Cortex is for and why it is worth running.
The verification needs a feedback channel that the reader actually sees.

Proposed Solution

Two small, docs-only changes:

• A feedback issue template for the laptop tool (.github/ISSUE_TEMPLATE/), with the fields
  that make a report useful: OS and architecture, the agent and model, what you expected the
  numbers to tell you, what was confusing, and whether anything else on the machine broke. This
  pairs with the "what to attach to a bug report" list already in the troubleshooting page.
• One consistent "give feedback" call at the end of the first-run flow (laptop quickstart and
  the read-the-numbers page): tried it? tell us what the numbers did or did not tell you, linking
  to the template and to Slack.

Additional Context

Follow-up to the docs PR rossoctl/rossoctl#2551.
Not release-blocking. Docs live in rossoctl/rossoctl under docs/; the issue template lives in this
repo. Part of the Cortex v0.9.0 epic as a follow-up,
not a P0.

Related: #844 (help users understand Context Guru),
and the sibling tooling issues for the abctl footer and the install.sh success message.