Add per-query field boost directives to lexical search

[Mbeaulne]

Description

Adds support for per-query field boost directives in the lexical search syntax. Users can now include bracket expressions (e.g., upload [metadata^20] or upload [metadata+10, title-5]) in their search queries to dynamically adjust how much weight individual fields contribute to scoring for that specific query.

Supported operator formats within [...] blocks:

• ^N — multiply the field's base weight by N
• =N — set the field weight to an absolute value
• + / ++ / +++ — increment weight by the number of + characters
• - / -- / --- — decrement weight by the number of - characters
• +N / -N — add or subtract a numeric value

Field aliases are supported (e.g., title → name, desc → description, impl → implementation, input/output → io, meta → metadata).

Phrase bonuses are scaled proportionally to the adjusted field weights, keeping scoring consistent. Boost blocks are stripped from the query text before token parsing so they do not interfere with term matching.

Related Issue and Pull requests

Type of Change

• Bug fix
• New feature
• Improvement
• Cleanup/Refactor
• Breaking change
• Documentation update

Checklist

• I have tested this does not break current pipelines / runs functionality
• I have tested the changes on staging

Screenshots (if applicable)

Test Instructions

1. Run the test suite with npm test (or equivalent) and confirm the new "supports per-query field boosts in bracket directives" test passes alongside existing lexical search tests.
2. Perform a manual search using a query like upload [metadata^20] and verify that results with matching metadata rank above results that only match on name/title.
3. Confirm that the bracket directive text itself does not appear as a matched token or affect unrelated results.

Additional Comments

The field weight overrides are scoped entirely to the parsed query and do not mutate the global FIELD_WEIGHTS constant.

[github-actions]

🎩 Preview

A preview build has been created at: 06-29-query_weight_change/66f76ec

[Mbeaulne]

Warning

This pull request is not mergeable via GitHub because a downstack PR is open. Once all requirements are satisfied, merge this PR as a stack on Graphite.
Learn more

• Add per-query field boost directives to lexical search #2472 👈 (View in Graphite)
• Cache search index in query and show skeleton while typing #2471
• Add source filter bar to editor component search #2470
• Add source to component search v1 and v2 #2469
• Add editor component search loading skeleton #2468
• Reduce lexical search result limit and field weights #2467
• master

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