fix: open release version-bump pull requests

[carlostasada]

No description provided.

[greptile-apps]

Greptile Summary

This PR moves the post-release version bump into a pull-request flow. The main changes are:

• Authenticated release-time tag fetches.
• An automated branch and PR for the next snapshot version.
• Snapshot publication after the version-bump PR is merged.
• Updated maintainer release documentation.
• A development version bump to 0.1.2-SNAPSHOT.

Confidence Score: 4/5

The automated version-bump PR can miss required checks and cannot recover from an orphaned remote branch.

PR creation with GITHUB_TOKEN does not trigger the Build workflow's pull-request event. A successful branch push followed by a failed PR API call leaves reruns blocked by a non-fast-forward push.

.github/workflows/release.yml

T-Rex Logs

What T-Rex did

• Ran the Orphaned Branch Blocks Recovery test using a local Git and gh-stub harness and reproduced the orphaned-branch scenario, including an initial push and a simulated gh pr create failure.
• In a fresh rerun, observed no open pull request and a distinct commit was created from the same main base.
• The rerun's push to origin was rejected as non-fast-forward before the pull request creation could run.
• Verified token-created PR checks do not automatically trigger runs under a read-only or non-authenticated host; the harness showed no PR creation and no repository mutation.
• Regression suite completed with all 45 tests passing and the fixture changed only gradle.properties, confirming no tracked or staged modifications.

_{Ran code and verified through T-Rex}

Important Files Changed

Filename	Overview
.github/workflows/release.yml	Adds authenticated fetches and replaces the direct version push with an automated pull request, but the new flow has check-triggering and partial-failure recovery gaps.
AGENTS.md	Updates the documented release process to describe the pull-request-based version bump.
CONTRIBUTING.md	Adds maintainer instructions for publishing a release and merging the next-version pull request.
gradle.properties	Advances the development version from 0.1.0-SNAPSHOT to 0.1.2-SNAPSHOT.

_{Reviews (1): Last reviewed commit: "Merge branch 'main' into fix/release-ver..." | Re-trigger Greptile}

[greptile-apps]

Orphaned Branch Blocks Recovery

If this push succeeds but gh pr create fails, the remote branch remains without an open PR. A rerun creates a new local commit with a different identity, and this push is rejected as non-fast-forward, so the version-bump PR cannot be opened without manually deleting or reconciling the branch. The same failure occurs when a closed PR leaves its branch behind.

[greptile-apps]

Token-Created PR Skips Checks

This command creates the PR with the repository GITHUB_TOKEN. GitHub does not start new workflow runs for events produced by that token, so the Build workflow's pull_request checks will not run for this PR; if those checks are required by branch protection, the automated version bump cannot be merged.