V1 resolver: move PR/issue context into initial user message (#12983)

Co-authored-by: openhands <openhands@all-hands.dev>

openhands/integrations/templates/resolver/github/issue_comment_initial_message.j2

@@ -0,0 +1,31 @@
+You are requested to fix issue #{{ issue_number }}: "{{ issue_title }}" in a repository.
+A comment on the issue has been addressed to you.
+
+# Issue Body
+{{ issue_body }}
+
+# Comment
+{{ issue_comment }}
+
+{% if previous_comments %}
+# Previous Comments
+For reference, here are the previous comments on the issue:
+
+{% for comment in previous_comments %}
+- @{{ comment.author }} said:
+{{ comment.body }}
+{% if not loop.last %}
+
+{% endif %}
+{% endfor %}
+{% endif %}
+
+# Guidelines
+
+1. Review the task carefully.
+2. For all changes to actual application code (e.g. in Python or Javascript), add an appropriate test to the testing directory to make sure that the issue has been fixed
+3. Run the tests, and if they pass you are done!
+4. You do NOT need to write new tests if there are only changes to documentation or configuration files.
+
+# Final Checklist
+Re-read the issue title, body, and comments and make sure that you have successfully implemented all requirements.

openhands/integrations/templates/resolver/github/pr_update_initial_message.j2

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+You are checked out to branch {{ branch_name }}, which has an open PR #{{ pr_number }}: "{{ pr_title }}".
+A comment on the PR has been addressed to you.
+
+# PR Description
+{{ pr_body }}
+
+{% if file_location %}
+# Comment location
+The comment is in the file `{{ file_location }}` on line #{{ line_number }}.
+{% endif %}
+
+# Comment
+{{ pr_comment }}
+
+{% if comments %}
+# Previous Comments
+You may find these other comments relevant:
+{% for comment in comments %}
+- @{{ comment.author }} said at {{ comment.created_at }}:
+{{ comment.body }}
+{% if not loop.last %}
+
+{% endif %}
+{% endfor %}
+{% endif %}
+
+# Steps to Handle the Comment
+
+## Understand the PR Context
+Use the $GITHUB_TOKEN and GitHub API to:
+    1. Retrieve the diff against the base branch (typically main) to understand the changes
+    2. Fetch the PR body and the linked issue for context
+
+## Process the Comment
+If it's a question, answer it.
+
+If it requests a code update:
+    1. Modify the code accordingly in the current branch
+    2. Commit your changes with a clear commit message
+    3. Verify if the branch is on a fork, and make sure the remote is correct
+    4. Push the changes to GitHub to update the PR.