fix(search): Tune MiniSearch to reduce over-inclusive results

[vredchenko]

Problem

Search results appear overly inclusive, returning too many loosely related matches.

Areas to Investigate

MiniSearch Configuration

1. Fuzzy matching: Currently fuzzy: 0.2 (~20% variance). Reduce to 0.1 or disable.
2. Prefix matching: prefix: true matches partial words. May be too broad.
3. Field boosting: Weight title matches higher than body content.
4. Minimum score: Filter out low-confidence matches below threshold.

GitHub Search

• Narrow queries with qualifiers like in:title
• Require exact phrase matching

Proposed Solution

Add tuning parameters to webui-config.ts to make these adjustable:

searchTuning: {
  fuzzy: 0.1,
  prefix: false,
  minScore: 0.5,
  fieldBoosts: { title: 3, content: 1 }
}

Request for Feedback

Need example queries that demonstrate over-inclusivity to identify root cause.

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From PR #124 review comment (Item 13)