Convert TypeSymbol and FileSymbol from int64 to uint64

[Copilot]

TypeSymbol and FileSymbol represent binary encodings, not signed integers. Using int64 required unnecessary conversions and could produce unexpected behavior with large values.

Changes

• Struct definitions: Changed TypeSymbol and FileSymbol fields from int64 to uint64 in FrameContent, FileMetadata, and ScannedFile structs
• Binary encoding/decoding: Removed int64/uint64 conversions in UnmarshalBinary and EncodeTo methods
• Scanner: Updated to use strconv.ParseUint and proper uint64 array indexing for chunk numbers
• Extraction: Removed unnecessary type conversions when formatting symbols

// Before: Required conversion and could mishandle large values
m.FrameContents[i].TypeSymbol = int64(binary.LittleEndian.Uint64(data[offset:]))
fileType := strconv.FormatUint(uint64(fc.TypeSymbol), 16)

// After: Direct handling as uint64
m.FrameContents[i].TypeSymbol = binary.LittleEndian.Uint64(data[offset:])
fileType := strconv.FormatUint(fc.TypeSymbol, 16)

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[Copilot]

Pull request overview

This PR converts TypeSymbol and FileSymbol fields from int64 to uint64 throughout the codebase, improving type correctness since these fields represent binary encodings rather than signed integers. The change eliminates unnecessary type conversions and prevents potential issues with large unsigned values being interpreted as negative numbers.

Key changes:

• Updated struct field types for TypeSymbol and FileSymbol to uint64 in FrameContent, FileMetadata, and ScannedFile
• Simplified binary encoding/decoding by removing int64/uint64 conversions in marshaling operations
• Updated scanner parsing logic to use strconv.ParseUint instead of strconv.ParseInt

Reviewed changes

Copilot reviewed 4 out of 5 changed files in this pull request and generated no comments.

File	Description
pkg/manifest/scanner.go	Changed ScannedFile fields to uint64, updated parsing to use strconv.ParseUint, and adjusted array growth condition to use uint64 comparisons
pkg/manifest/package.go	Removed unnecessary uint64 conversions when formatting symbols for file extraction
pkg/manifest/manifest.go	Updated FrameContent and FileMetadata struct definitions to use uint64, and removed conversions in UnmarshalBinary and EncodeTo methods
pkg/manifest/benchmark_test.go	Updated test data initialization to use uint64 literals for consistency with new field types

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