ci(opencode): bump pinned OpenCode to v1.19.3

.github/opencode-version.txt

@@ -1 +1 @@
-1.18.30
+1.19.3

.github/workflows/bump-opencode.yml

@@ -91,6 +91,21 @@ jobs:
         run: |
           echo "${{ steps.latest.outputs.version }}" > .github/opencode-version.txt
 
+      # The V1 leg of OC2 parity relies on a capture tied to the exact pin.
+      # Generate it before opening a PR so changed host behavior is reviewed
+      # with the version bump, not discovered by the merge queue.
+      - name: Capture OpenCode 1 OC2 contracts
+        if: steps.compare.outputs.drift == 'true'
+        env:
+          CAPTURE_VERSION: ${{ steps.latest.outputs.version }}
+        run: |
+          set -euo pipefail
+          echo "Recapturing host1 provider and edit-family contracts for $CAPTURE_VERSION"
+          if ! node tests/docker/opencode2/contract/capture-host1-contracts.mjs "$CAPTURE_VERSION"; then
+            echo "::error::OpenCode 1 contract capture failed. Review the host behavior and rerun node tests/docker/opencode2/contract/capture-host1-contracts.mjs $CAPTURE_VERSION on Linux x64 before opening the bump PR."
+            exit 1
+          fi
+
       # Org policy blocks GITHUB_TOKEN from creating pull requests
       # ("GitHub Actions is not permitted to create or approve pull
       # requests"), which made every run of this lane fail at the PR step
@@ -135,7 +150,17 @@ jobs:
           git remote set-url origin "$remote_url"
 
           git checkout -b "$branch"
-          git add .github/opencode-version.txt
+          descriptor_branch="${branch//\//-}"
+          descriptor="benchmarks/aft-search/slice-descriptors/${descriptor_branch}.json"
+          cat > "$descriptor" <<'EOF'
+          {
+            "slice_class": "non_ranking",
+            "targeted_mechanism": "none",
+            "kind": "harness",
+            "fixtures": ["harness-goldens"]
+          }
+          EOF
+          git add .github/opencode-version.txt "$descriptor" tests/docker/opencode2/contract/
           git commit -m "ci(opencode): bump pinned OpenCode to v${new}
 
           Auto-generated by .github/workflows/bump-opencode.yml.

benchmarks/aft-search/slice-descriptors/ci-bump-opencode-1.19.3.json

@@ -0,0 +1,6 @@
+{
+  "slice_class": "non_ranking",
+  "targeted_mechanism": "none",
+  "kind": "harness",
+  "fixtures": ["harness-goldens"]
+}

packages/opencode-plugin/test/load-matrix/load-matrix.ts

@@ -113,7 +113,7 @@
     timeout: options.timeoutMs,
   });
   if (result.status !== 0 && !options.allowFailure) {
     throw new Error(
       `${command} ${args.join(" ")} failed (${result.status ?? result.error?.message ?? "unknown"})\n${result.stdout}\n${result.stderr}`,
     );
   }
@@ -2255,7 +2255,14 @@
   });
 
   test("modern V1 version is sourced only from the repository pin", async () => {
-    expect(modernV1).toMatch(/^1\.18\./);
+    const pinnedVersion = (
+      await readFile(join(repoRoot, ".github/opencode-version.txt"), "utf8")
+    ).trim();
+    expect(pinnedVersion).toMatch(
+      /^(0|[1-9]\d*)\.(0|[1-9]\d*)\.(0|[1-9]\d*)(?:-(?:0|[1-9]\d*|\d*[A-Za-z-][0-9A-Za-z-]*)(?:\.(?:0|[1-9]\d*|\d*[A-Za-z-][0-9A-Za-z-]*))*)?(?:\+[0-9A-Za-z-]+(?:\.[0-9A-Za-z-]+)*)?$/,
+    );
+    expect(modernV1).toBe(pinnedVersion);
+
     const files = await fixtureFiles(join(pluginRoot, "test"));
     const literals: string[] = [];
     for (const path of files) {
@@ -2266,7 +2273,9 @@
       // finding rather than protect it.
       if (path.endsWith(".md")) continue;
       const text = await readFile(path, "utf8");
-      if (/\b1\.18\.\d+\b/.test(text)) literals.push(path);
+      if (text.split(/[^0-9A-Za-z.+-]+/).includes(pinnedVersion)) {
+        literals.push(path);
+      }
     }
     expect(literals).toEqual([]);
   });
@@ -3152,7 +3161,7 @@
     } else {
       expect(operatorAfter).toEqual(operatorBefore);
     }
     expect(hostCanaries.map(({ label }) => label)).toEqual([
       "v1-server",
       "v1-tui",
       "v2-bun",