Share hash formatting and fixed-width header helpers

[pathawks]

Summary

• add a shared Hashes type for CUE/DAT hash calculation and hex formatting
• keep DAT hash attributes lowercase while preserving uppercase human-facing hash output
• add shared helpers for fixed-width and null-padded header strings
• move common Nintendo disc DAT metadata and typed-header parsing into the shared Nintendo disc module

Verification

• cargo fmt --check
• cargo test
• cargo clippy --all-targets --all-features -- -D warnings

[Copilot]

Pull request overview

This pull request centralizes hash computation/formatting and fixed-width / null-padded header string parsing, then updates multiple systems and output pipelines to use the shared utilities for consistent DAT and human-facing output.

Changes:

• Introduces a shared output::hash module (Hashes, compute_hashes, and hex formatting helpers) and wires it into DAT/CUE/disc output paths.
• Adds shared string-reading helpers in systems::helpers and replaces duplicated fixed-width / null-padded parsing across multiple systems.
• Moves Nintendo disc DAT metadata + typed header parsing into the shared Nintendo disc module and updates Wii/GameCube parsing to use typed parsing.

Reviewed changes

Copilot reviewed 18 out of 18 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
src/systems/wii.rs	Switches Wii parsing to typed Nintendo-disc parsing and delegates DAT metadata to the shared header.
src/systems/segacd.rs	Replaces local fixed-width string extraction with shared read_fixed_string.
src/systems/odyssey2.rs	Uses shared SHA1 formatting helper for consistent display output.
src/systems/helpers.rs	Adds shared fixed-width and null-padded string readers used by multiple systems.
src/systems/gba.rs	Uses shared null-padded string reader for title parsing.
src/systems/gamecube.rs	Switches GameCube parsing to typed Nintendo-disc parsing and delegates DAT metadata to the shared header.
src/systems/gameboy.rs	Uses shared null-padded string reader for title parsing.
src/systems/fds.rs	Uses shared SHA1 formatting helper for consistent display output.
src/systems/disc/sega_ip.rs	Replaces local fixed-width string extraction with shared read_fixed_string.
src/systems/disc/pvd.rs	Replaces local fixed-width string extraction with shared read_fixed_string.
src/systems/disc/nintendo_disc.rs	Adds typed parsing + shared DAT metadata on NintendoDiscHeader; centralizes title parsing helpers.
src/systems/disc/mod.rs	Switches disc SHA1 formatting import to the new output::hash module.
src/systems/atari/lynx.rs	Uses shared null-padded string reader for header strings.
src/output/mod.rs	Exposes the new output::hash module.
src/output/hash.rs	Adds shared hash computation + hex formatting utilities (Hashes, compute_hashes, helpers).
src/output/dat.rs	Refactors DAT generation to use shared Hashes and centralizes game metadata detection.
src/output/cue.rs	Refactors CUE hashing to use shared Hashes/compute_hashes and shared SHA1 formatting.
src/main.rs	Updates CLI output to use Hashes for SHA1 display (and removes now-unneeded import).

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