KWIC + n-gram analysis

[aahafez]

No description provided.

[Copilot]

Pull request overview

Adds backend support for KWIC (keyword-in-context) search and project-level n‑gram frequency analysis backed by Elasticsearch, exposing new analysis endpoints for the frontend.

Changes:

• Introduces /analysis/kwic endpoint and KWIC snippet extraction/sorting logic.
• Introduces /analysis/ngrams endpoint and Elasticsearch aggregation to fetch frequent n‑grams.
• Extends the SDoc Elasticsearch index mapping/settings with unigram/bigram/trigram subfields and analyzers.

Reviewed changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 15 comments.

Show a summary per file

File	Description
docker/compose.yml	Clarifies Elasticsearch JVM heap env var comment.
backend/src/modules/analysis/kwic_analysis.py	Implements KWIC snippet extraction and frequency-based sorting.
backend/src/modules/analysis/analysis_endpoint.py	Adds /analysis/kwic and /analysis/ngrams endpoints.
backend/src/core/doc/sdoc_kwic_dto.py	Adds DTOs/enums for KWIC + n‑gram responses.
backend/src/core/doc/sdoc_elastic_index.py	Updates ES index settings/mappings to support n‑grams + fast-vector-highlighter.
backend/src/core/doc/sdoc_elastic_crud.py	Adds ES CRUD methods for KWIC search and n‑gram aggregation.