feat(site): add a "who it's for" section above the problem pitch

[dvcdsys]

Why

The page currently opens with "Grep doesn't scale to the way you actually
search code." That argument only works on someone who has already decided
they have that problem. A visitor arriving cold — from a directory, a
search result, a link in a thread — asks something cheaper first: is this
for me?

What

A new Who it's for section between the hero and The problem, framed as
the visitor's week rather than the product's feature list. Six situations,
each mapping to something that already exists:

Situation	What backs it
Your agent should already know the codebase.	hooks + skills
You research code you didn't write.	semantic search
You are writing the spec before the code.	references, touchpoints
You are doing a security pass.	five search modes over the whole tree
Your system is a dozen services in a dozen repos.	workspaces, hybrid ranking
Your team is spread out. So are its agents.	shared server, roles, view-groups, API keys

Nothing here is a new promise — the section qualifies readers against
shipped behaviour.

The security card states outright that cix does not scan for CVEs — it
finds everything worth scanning. Implying a scanner would be both wrong
and easy to disprove; "where to look" is the honest and still-useful claim.

Design notes

• Reuses .why-grid, so the six cards fall into two rows and the existing
  mobile single-column rule applies with no new responsive CSS.
• The card marker is a small arrow rather than the display-size numerals used
  by The problem — with 01/02/03 in both, the sections would read as one
  long numbered list.

Test plan

• npm run build — green.
• Rendered at 1456px: 2 × 3 grid, even row heights, clean transition into
  The problem.
• Rendered at 548px: single column, scrollWidth == innerWidth (no horizontal
  overflow).

🤖 Generated with Claude Code