v2.60.0: EcuArchDetector: ISA fingerprinter for unknown flat ECU ROM images.** Five discr

EcuArchDetector: ISA fingerprinter for unknown flat ECU ROM images. Five discriminators
identify the instruction set of a raw binary with no ELF/IHEX wrapper, returning a HIGH/MEDIUM/LOW
confidence verdict and the best-match ISA token, enabling automatic decoder selection before any
disassembly step.

• EcuArchDetector: detect() → ArchDetectResult; candidates() → list[ArchCandidate] sorted by score
• ArchDetectResult: arch, confidence (HIGH/MEDIUM/LOW), score, reason, candidates, is_confident
• ArchCandidate: arch, score, reason
• ARM Cortex-M: LE vector table — MSP in SRAM 0x20000000–0x3FFFFFFF + Thumb reset handler; score 0.90 (both) / 0.55 (MSP only)
• M68K/CPU32: BE reset vector in-range + LINK.W A6, #-N prologue density; score 0.85 / 0.70 / 0.35
• PPC32 Book E: primary opcode density (0x08-0x0F, 0x38-0x3F, 0x80-0x9F ranges); fires at ≥ 35% density
• PPC VLE: (byte0 & 0x90) == 0x10 halfword density; score = min(density * 2.5, 0.92) at ≥ 15% density
• SH-2A: BE reset vector at offset 4 + STS.L PR (0x4F22) density + RTS (0x000B) density; score 0.88/0.75/0.60/0.40
• from_path() / from_bytes() convenience wrappers; sample_size=0 scans full image
• 31 tests; FORGE gate: PASSED (0 findings)

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