refactor(lineage): tighten impact-mark internals; fix amber contrast

Cleanups to the Lineage tab impact-mark code introduced in this branch:

- Extract effectiveStatus / colorForEffective helpers — single source for
  the "unchanged + cllImpacted → impacted" mapping that was duplicated
  across StatusDot, getNodeStatusColor, and FocusCard.
- Split the impact chip into ChipButton (interactive) and ChipBadge
  (display-only), removing the polymorphic component={x ? "button" :
  "span"} pattern and its dangling type="button" attribute.
- Flatten the triple-nested chipTitle ternary into a getChipTitle
  helper with early returns.
- Rename DirectRow props for distinct intent: impacted →
  decorateAsImpacted (drives the rail/tint/arrow), cllImpacted →
  dotImpacted (drives the dot color).
- Add a comment marking the trailing arrow icon as direction-agnostic
  (the tooltip carries direction).

Also fix amber legibility on light backgrounds: the canvas amber
rgb(252 211 77) reads fine as a filled shape (dot, rail, chip bg) but
fails contrast as a thin-stroke icon or small text on white. Add an
impactedTextColor() helper (deeper amber rgb(146 64 14) in light mode,
light yellow in dark mode) and apply it to:
- the trailing impact-mark arrow icon in DirectRow
- the FocusCard "Impacted" pill text and border (when status is
  impacted)

The other impact visuals — left rail, dot, chip background — keep the
canvas amber since brightness reads correctly on filled shapes.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Signed-off-by: Wei-Chun, Chang <wcchang@infuseai.io>

Author: wcchang1115