fix(core): pin opencode version to avoid GitHub API rate limit failures

Pin opencode to version 1.2.27 by passing --version flag to the install
script. Without a pinned version, the installer fetches the latest version
from the GitHub API (api.github.com/repos/anomalyco/opencode/releases/latest),
which fails with "Failed to fetch version information" when rate-limited or
network-throttled during Docker builds in CI.

This is the root cause of the E2E (Clone cache) CI failure.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: konard

packages/lib/src/core/templates/dockerfile.ts

@@ -64,12 +64,14 @@ RUN claude --version
 RUN npm install -g @google/gemini-cli@latest --force
 RUN gemini --version`
 
+const openCodeVersion = "1.2.27"
+
 const renderDockerfileOpenCode = (): string =>
   `# Tooling: OpenCode (binary)
 RUN set -eu; \
   for attempt in 1 2 3 4 5; do \
     if curl -fsSL --retry 5 --retry-all-errors --retry-delay 2 https://opencode.ai/install \
-      | HOME=/usr/local bash -s -- --no-modify-path; then \
+      | HOME=/usr/local bash -s -- --version ${openCodeVersion} --no-modify-path; then \
       exit 0; \
     fi; \
     echo "opencode install attempt \${attempt} failed; retrying..." >&2; \