feat: allow gitea.issue.comment for author and reviewer profiles (#137)

- Add aliases 'issue.comment' and 'issue_comment' to GITEA_OPERATION_ALIASES so short names normalize to gitea.issue.comment
- Grant 'issue.comment' (and short) in v2 example profiles for example-author and example-reviewer
- Grant in gitea-mcp.example.json mdcps-reviewer
- Update docs example profiles
- Add test coverage for new aliases and normalization

This enables gitea_create_issue_comment and list for profiles that include it, while preserving fail-closed for others and separation of duties (issue.comment does not imply pr.review etc).

Closes #137

gitea-mcp.example.json

@@ -30,7 +30,7 @@
       },
       "default_owner": "MDCPS",
       "execution_profile": "mdcps-reviewer",
-      "allowed_operations": ["read", "review", "approve", "merge"],
+      "allowed_operations": ["read", "review", "approve", "merge", "issue.comment"],
       "forbidden_operations": ["branch.push", "pr.create"]
     },
     "prgs-env": {