fix(github action): don't die on rate-limited version lookup

[sfmullen]

Problem

The GitHub action's version step:

VERSION=$(curl -sf https://api.github.com/repos/anomalyco/opencode/releases/latest | grep -o '"tag_name": *"[^"]*"' | cut -d'"' -f4)
echo "version=${VERSION:-latest}" >> $GITHUB_OUTPUT

shell: bash composite steps run with -e -o pipefail, so when the unauthenticated curl is rate-limited (GitHub-hosted runners share IP pools against the 60 req/hr unauthenticated API limit, so this happens regularly), the failed command substitution kills the step and the ${VERSION:-latest} fallback on the next line is unreachable. The consumer's whole job fails at setup. We hit this intermittently in CI: the action step exits 1 about 23s in, and a plain re-run goes green.

Fix

Two small changes to the version step, nothing caller-facing:

1. Authenticate the lookup with github.token (always available inside composite actions; a public-repo read needs no scopes). This removes the rate-limit cause.
2. || true on the substitution so the documented ${VERSION:-latest} fallback is actually reachable if the lookup still fails for any other reason (e.g. a token that is not valid for api.github.com on GHES runners).

Worst case becomes what the code already intended: fall back to latest and let the install script resolve the version.

[github-actions]

This PR doesn't fully meet our contributing guidelines and PR template.

What needs to be fixed:

• PR description is missing required template sections. Please use the PR template.

Please edit this PR description to address the above within 2 hours, or it will be automatically closed.

If you believe this was flagged incorrectly, please let a maintainer know.

[github-actions]

Hey! Your PR title fix(github action): don't die on rate-limited version lookup doesn't follow conventional commit format.

Please update it to start with one of:

• feat: or feat(scope): new feature
• fix: or fix(scope): bug fix
• docs: or docs(scope): documentation changes
• chore: or chore(scope): maintenance tasks
• refactor: or refactor(scope): code refactoring
• test: or test(scope): adding or updating tests

Where scope is the package name (e.g., app, desktop, opencode).

See CONTRIBUTING.md for details.