[DIT-13468]: Send scanned path scope in the CLI scan

[laurakoye]

Overview

ditto scan now tells the server where it looked, so a later scan only reconciles code links inside the scanned scope instead of assuming everything it didn't see was deleted.

Two fields on POST /v2/scan, alongside the repoRelativeRoot that shipped in #155:

scan target	repoRelativeRoot	scannedAllPaths	scannedPaths
repo root	""	true	omitted
subdirectory src	"src"	false	["src"]
not a git repo	omitted	omitted	omitted

scannedPaths entries are relative to the repo root, matching what ditto-app #9391 validates. Where the scope is omitted, the server's scannedAllPaths: false default applies, so such a scan can never mark a code link removed.

ditto scan takes one path, so scannedPaths is always a one-element list restating repoRelativeRoot. Sent anyway so DIT-13449's reconcile has one shape to code against.

Bumps the package to 5.8.1 — nothing user-visible changes.

Context

• DIT-13468
• Needs ditto-app #9391 to verify — until it merges, zod strips both fields at the API boundary. Safe to merge before that; the server just ignores them.

Test Plan

Against a local app on the #9391 branch. Records checked in Compass: ditto_db_v2 → producttextdetections, filter { repoKey: { $exists: true } }.

• yarn test lib/src/http/scan.test.ts
• yarn scan ~/Desktop/Ditto/v0-demo → repoRelativeRoot: "", scannedAllPaths: true, no scannedPaths
• yarn scan ~/Desktop/Ditto/v0-demo/src → repoRelativeRoot: "src", scannedAllPaths: false, scannedPaths: ["src"]
• yarn scan /tmp/not-a-repo → no git fields on the record