Automatically create -repo alias when indexing repositories

[kapral18]

Problem

Currently, when indexing a repository, the indexer creates the main index and _settings index, but does not create a -repo alias. This requires users to manually create aliases for the MCP server to discover indices, which is a poor user experience.

Solution

Automatically create a <indexName>-repo alias pointing to the main index when:

1. A new index is created
2. An existing index is used (for backward compatibility with already-indexed repos)

Implementation

• Add createRepoAlias() function that:

  • Creates alias with pattern <indexName>-repo
  • Checks if alias already exists (idempotent)
  • Verifies index exists before creating alias
  • Handles errors gracefully (non-blocking)

• Integrate into createIndex():

  • Call createRepoAlias() after successful index creation
  • Also call for existing indices to ensure aliases are created retroactively

Benefits

✅ Works seamlessly with MCP server's alias-based discovery (primary strategy)
✅ No manual steps required for users
✅ Backward compatible (creates aliases for existing indices)
✅ Non-blocking (alias creation failures don't break indexing)
✅ Complements the MCP server's _settings fallback strategy

Related

This complements the MCP server improvement in:

• Improve list_indices to discover indices via _settings pattern fallback semantic-code-search-mcp-server#33
• feat: improve list_indices with dual discovery and consistent index name display semantic-code-search-mcp-server#34

[kapral18]

This complements the MCP server improvements in:

• Improve list_indices to discover indices via _settings pattern fallback semantic-code-search-mcp-server#33
• feat: improve list_indices with dual discovery and consistent index name display semantic-code-search-mcp-server#34

Together, these changes provide a complete solution:

1. Indexer automatically creates -repo aliases (this PR)
2. MCP server discovers indices via aliases (primary) and _settings pattern (fallback)

[kapral18]

Closing in favor of alias-first architecture. See new issue #XXX for details.

[kapral18]

Closing in favor of alias-first architecture. See #132 for details.