Change Impact Assessment Tool

Fix stale "costed" wording, trim two more provenance footnotes

Landing page and Add-a-role lede claimed a "costed plan"/"costed
package" that no longer exists since the Adoption tab's cost section
was cut; reworded to "resourced plan"/"resourced package", matching
what resourcedPlan() actually computes. Also relabeled the now-unused
ROI-model section comment for clarity.

Remove the trailing provenance/1:15-ratio footnote after the one-pager's
Measurement section, and the same pair from the bottom of the
Stakeholder Impact page.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>