Apply overrides.json and relaxed name matching to display Google ratings

[ethan-CCY]

Motivation

• The site did not reliably show Google ratings because overrides could fail to be fetched or matched to items.
• The fetch path and matching rules needed to be more robust for GitHub Pages and varied parking names.
• A relaxed matching rule (e.g. ignoring whitespace and the word 停車場) helps match keys produced by external scripts.
• A debug hook is useful to quickly confirm merges in the browser console.

Description

• Updated the overrides file path to ./overrides.json and added a DEBUG_OVERRIDES flag in assets/app.js.
• Added normalizeOverrideKey() and buildOverrideMaps() to prepare exact and relaxed override maps for matching.
• Changed the merge in initialize() to try exact match first, then relaxed match, and apply ov.google_rating -> item.googleRating and ov.google_review_count -> item.googleReviewCount while collecting unmatched item names.
• Added console logging for the first few override keys, first item name/rating when DEBUG_OVERRIDES is enabled, and a printed 未匹配清單 for unmatched items.

Testing

• No automated tests were run for this static site change.

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Codex Task