feat: add 13 read tools (PR files/commits, comments, branches, releases, milestones, org/status/languages/topics)

Expands the read surface so the MCP can inspect more of Gitea:

- list_pull_request_files, list_pull_request_commits, list_issue_comments
- list_branches, get_branch
- get_release, get_latest_release, list_milestones
- get_commit_status
- list_org_repositories, list_organizations
- get_repo_languages, list_repo_topics

Each: arg schema (extra=forbid; GitRef on branch/sha fields), Gitea client
method with url-encoded path segments, bounded handler, MCP registration
(read-only), server wiring, docs, and parametrized success tests.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/aegis_gitea_mcp/server.py

@@ -61,14 +61,27 @@ from aegis_gitea_mcp.security import sanitize_data
 from aegis_gitea_mcp.tools.arguments import extract_repository, extract_target_path
 from aegis_gitea_mcp.tools.read_tools import (
     compare_refs_tool,
+    get_branch_tool,
     get_commit_diff_tool,
+    get_commit_status_tool,
     get_issue_tool,
+    get_latest_release_tool,
     get_pull_request_tool,
+    get_release_tool,
+    get_repo_languages_tool,
+    list_branches_tool,
     list_commits_tool,
+    list_issue_comments_tool,
     list_issues_tool,
     list_labels_tool,
+    list_milestones_tool,
+    list_org_repositories_tool,
+    list_organizations_tool,
+    list_pull_request_commits_tool,
+    list_pull_request_files_tool,
     list_pull_requests_tool,
     list_releases_tool,
+    list_repo_topics_tool,
     list_tags_tool,
     search_code_tool,
 )
@@ -344,6 +357,19 @@ TOOL_HANDLERS: dict[str, ToolHandler] = {
     "list_labels": list_labels_tool,
     "list_tags": list_tags_tool,
     "list_releases": list_releases_tool,
+    "list_pull_request_files": list_pull_request_files_tool,
+    "list_pull_request_commits": list_pull_request_commits_tool,
+    "list_issue_comments": list_issue_comments_tool,
+    "list_branches": list_branches_tool,
+    "get_branch": get_branch_tool,
+    "get_release": get_release_tool,
+    "get_latest_release": get_latest_release_tool,
+    "list_milestones": list_milestones_tool,
+    "get_commit_status": get_commit_status_tool,
+    "list_org_repositories": list_org_repositories_tool,
+    "list_organizations": list_organizations_tool,
+    "get_repo_languages": get_repo_languages_tool,
+    "list_repo_topics": list_repo_topics_tool,
     # Write-mode tools
     "create_issue": create_issue_tool,
     "update_issue": update_issue_tool,