docs: add comprehensive documentation for fuzzy_match utility

[AlHeloween]

Added industry-standard documentation for the `fuzzy_match` and
`fuzzy_indices` functions in `codex-rs/utils/fuzzy-match/src/lib.rs`.
The documentation follows Google Style and includes:

• High-level module summary and architectural context.
• Explicit parameter and return value definitions.
• Detailed internal logic and complexity analysis (Time: O(N+M), Space: O(N+M)).
• Handled exceptions and edge cases.
• "Quick Start" usage examples.
• Dependency listing.

Verified with `cargo test -p codex-utils-fuzzy-match`, including doctests.

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PR created automatically by Jules for task 12523197037190092627 started by @AlHeloween

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