indexer: file-level delta indexing keyed on (path, content_sha) (#104) - #114

Node.js 20 is deprecated. The following actions target Node.js 20 but are being forced to run on Node.js 24: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5, astral-sh/setup-uv@e4db8464a088ece1b920f60402e813ea4de65b8f. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/