[ci] Update agentic workflows to claude-opus-4.8 (#1461)

The `claude-opus-4.6` model is retired/unsupported, producing this error in gh-aw workflow runs:

> Error: model 'claude-opus-4.6' is retired or unsupported. Did you mean 'claude-opus-4.8'?

Update the model reference in `.github/workflows/java-interop-reviewer.md` to `claude-opus-4.8` and recompile the `.lock.yml` via `gh aw compile`. The recompile also generated `agentics-maintenance.yml` and updated pinned action versions.

Follow-up to dotnet/android#11646.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: jonathanpeppers

.github/aw/actions-lock.json

@@ -5,6 +5,11 @@
       "version": "v9.0.0",
       "sha": "3a2844b7e9c422d3c10d287c895573f7108da1b3"
     },
+    "github/gh-aw-actions/setup-cli@v0.79.6": {
+      "repo": "github/gh-aw-actions/setup-cli",
+      "version": "v0.79.6",
+      "sha": "5c2fe865bb4dc46e1450f6ee0d0541d759aea73a"
+    },
     "github/gh-aw-actions/setup@v0.79.6": {
       "repo": "github/gh-aw-actions/setup",
       "version": "v0.79.6",