#1093 fix(report): badge an exploration with the target its test started on

What and why

• The list reporter's exploreBadge read this.targets[0], the first configured target, while an exploration runs on the target --target selected (packages/e2e/src/report/list.ts).
• It now badges with the target the exploration's test started on, which test-started carries and precedes the explore started progress; the first configured target remains the fallback.

Closes #1089

Verified

Ran it locally: yes

• Two web targets, capacity then mixed; e2e explore "Explore the page" --config e2e.targets.config.ts --target mixed --max-steps 1, no API key (the badge prints before the planner needs one). Same command on a main build.

main	this branch
❯ |capacity| Exploring Explore the page	❯ |mixed| Exploring Explore the page

report.json names run.results[0].targetId: "mixed" on both. The new unit test fails on main with expected ' ❯ |capacity| Exploring ...' to contain '|mixed|'.

Checklist

• Changeset added (pnpm changeset) for any change to a published package, or the change is testbed, docs, or CI only.
• Breaking change: title carries !, the changeset body names what breaks and what replaces it, and the deprecation warning landed a window earlier (stability policy in CONTRIBUTING.md).
• Docs updated in the same PR: the docs/**/*.mdx page for the behavior, and skills/e2e/ if the skill describes it.
• Contract change: emitted .d.ts reviewed, tests/types/sdk-types.ts updated; wire change edits the schema and both fixtures.
• Engine contract change (e2e/engine): changesets for e2e, @e2e-dev/web, and @e2e-dev/mobile.