fix: final-review wave — preview host INV-10 gate, thread status+offer contextValue tokens, establish-on-open baseline, polish

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

test/previewAnnotations.test.ts

@@ -63,6 +63,25 @@ describe("preview annotations (PUC-3/D21)", () => {
     expect(html).toContain("cw-del");
     expect(html).toContain("world");
   });
+  // Finding 4 (final whole-branch review, session native-surfaces-exec): the
+  // applied-proposal insertion mark used to hardcode tag: "claude", so a
+  // human-authored proposal (ProposalView.author = "human") still rendered
+  // cw-ins-claude. It must follow `p.author` (defaulting to "claude" only
+  // when the field is absent, per ProposalView's own documented default).
+  it("a human-authored pending proposal renders its applied text cw-ins-human, not cw-ins-claude", () => {
+    const src = "hello HUMAN world\n";
+    const html = render(src, {
+      ...base,
+      baselineText: "hello world\n",
+      spans: [],
+      proposals: [
+        { id: "p1", anchorStart: 6, anchorEnd: 11, replaced: "world", replacement: "HUMAN", author: "human" },
+      ],
+    });
+    expect(html).toContain('class="cw-ins-human"');
+    expect(html).not.toContain('class="cw-ins-claude"');
+    expect(html).toContain("HUMAN");
+  });
   // Task 8 (INV-32/33 coverage moved from f10Review.test.ts): a block with no
   // spans and no baseline divergence carries no cw- marks at all, even when
   // annotations are enabled — "changed since baseline" is the only trigger.