Search logic cleanup & error handling

[onmax]

Scope

This issue captures the remaining search cleanups that are not covered by pagination or shared SQL fragments.

Tasks

• Create a helper that normalizes search options (page, limit, origin, max distance) and share it across searchLocationsByText, searchLocationsByCategories, and searchLocationsBySimilarCategories. Coordinate with the pagination work in Fix SQL pagination instead of post-fetch slicing #67 and the fragment work in Create shared SQL fragment utilities #70 so the helpers stay aligned.
• Update both semantic and text search flows to use AND semantics when multiple categories are provided (reuse sqlFragments.categoryFilter once Create shared SQL fragment utilities #70 lands).
• Improve text search resilience by switching to websearch_to_tsquery or sanitizing tokens before calling to_tsquery.
• Handle GeoIP zero-coordinate responses without throwing (server/utils/geoip.ts).
• Reference the OpeningHours error handling added in Fix openNow filtering with real-time data #68 and ensure the shared helper calls it consistently.

Acceptance Criteria

• Option normalization lives in one place and all search utilities consume it.
• Category filters produce AND behaviour consistently across all search paths.
• Text search requests with special characters no longer cause Postgres syntax errors.
• Requests succeed when GeoIP returns 0 values.

Parent Issue

Part of #66

[onmax]

Current Status

Reviewing the codebase, here's the completion status:

Completed:

• ✅ Shared SQL fragment utilities exist ()
• ✅ OpeningHours error handling (completed in Fix openNow filtering with real-time data #68)

Remaining Tasks:

1. ❌ AND semantics for categories: \ lines 121 & 195 still use \ instead of \ (the AND version already exists in sql-fragments)
2. ❌ Text search resilience: Still using \ which fails on special characters - should switch to \ or add input sanitization
3. ❌ GeoIP error handling: \ throws error on zero coordinates instead of handling gracefully (e.g., returning null or default location)

The issue remains valid and should stay open.