feat: add price range and capacity filters to `/search-events`

[BigBen-7]

Description

SearchEventsRequest and filter_events_by_keywords only filter by event type, location, time, and general keywords. Users searching for "affordable concerts in Lagos" or "small intimate events" have no way to filter by price or venue capacity — two of the most common search criteria for ticket buyers.

Requirements & context

• Add to SearchEventsRequest:
  • min_price: Optional[float] and max_price: Optional[float]
  • max_capacity: Optional[int] (useful for "intimate" events)
• Update filter_events_by_keywords to apply these filters when present
• The NLP extract_keywords function should detect price intent keywords: "cheap", "affordable", "free" → set max_price=0 or max_price=5000; "premium", "VIP" → set min_price=10000
• Add the price hint detection to extract_keywords return dict as price_hints: { min_price, max_price }
• Write tests for each new filter individually and in combination

Suggested execution

git checkout -b feat/search-price-capacity-filters

• Update src/types_custom.py SearchEventsRequest
• Update src/search_utils.py
• Write tests

Guidelines

• PR must include: Closes #[issue_id]
• Timeframe: 48 hours

[TomikeDS]

@TomikeDS has applied to work on this issue as part of the Stellar Wave Program's 3rd wave.

i will love to work on this?

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