MNI-4: Nikon MakerNote Parser

[rpuneet]

Summary

Implement Nikon MakerNote parser for Epic #9 (Phase 2).

Format Specification - 3 VARIANTS

Type 1 (E990, D1)

• Header: "Nikon" + 0x00 0x01 0x00 (8 bytes)
• IFD Offset: +8
• Byte Order: Inherits from parent
• Offset Base: Absolute

Type 3 (D70, D100, D200+) - Most Common

• Header: "Nikon" + 0x00 0x02 0x00 + embedded TIFF header (18 bytes)
• IFD Offset: +18
• Byte Order: Embedded (check bytes 10-11 for II/MM)
• Offset Base: Relative to MakerNote start

Type 2 (E700-E950) - Legacy

• Header: None
• Uses Type 3 tag definitions
• Absolute offsets

Priority Tags (Phase 2)

Tag	Name	Type
0x0002	ISO	Short array
0x001D	SerialNumber	ASCII
0x0025	ShutterCount	Long
0x0084	Lens	Rational array
0x00A7	ShutterCount (alt)	Long

Encrypted Fields (skip initially)

• 0x0098: LensData - encrypted with serial-based key
• 0x00A8: FlashInfo - partially encrypted

Acceptance Criteria

• Detects all 3 Nikon variants
• Handles embedded byte order (Type 3)
• Decodes 15+ Nikon tags
• Gracefully skips encrypted fields
• Unit tests with real Nikon samples (NEF, JPG)

Blocked by: MNI-2 (Canon)
Parent: #9

[rpuneet]

Completed in PR #27