CE-WP-0006/0007: Capture view polish, workplans, and UX refinements

- Blob URL stability, scroll centre, strip-only visual guide
- Focus-gated linking, unlink clears overlay, field badge tooltips
- Capture layout (viewer centre), grey guide lines, Add field button
- Workplans CE-WP-0006 (done) and CE-WP-0007 (T01-T09 done, T10-T12 todo)
- Integration tests and viewer-url helpers

tests/integration/anchor-source-roundtrip.test.ts

@@ -42,7 +42,7 @@ beforeAll(async () => {
   );
 });
 
-describe("create + resolve round-trip — fixture corpus", () => {
+describe("create + resolve round-trip — fixture corpus", { timeout: 30_000 }, () => {
   for (const fixture of FIXTURES) {
     it(`${fixture.id}: known-good quote round-trips with confidence ≥ 0.9`, async () => {
       const bytes = new Uint8Array(readFileSync(resolve(FIXTURE_DIR, fixture.filename)));