[LE0-Lin]

Summary

• Reject duplicate decoded JSON member names at every repository-config depth instead of adopting the last value, including escaped names, equal-valued repeats and nested suppression objects. Diagnostic text does not echo duplicate member names or values.
• Reject non-standard NaN/Infinity constants and Boolean format versions. Preserve valid defaults, numeric version 1.0 compatibility, rule scores, missing-config behavior and baseline-governed thresholds/suppressions.
• Share one configuration document read/decoder with doctor so policy and schema metadata do not come from separate reads. Invalid configuration is operational failure for scan/feedback/compare/diff, or a structured config error for doctor; trusted threshold overrides cannot skip validation.
• Add 17 focused contracts including real local Git baseline/candidate rejection and worktree cleanup, privacy/overwrite checks and legitimate repeated names in separate objects/string literals. Extend installed-wheel acceptance across both console aliases, module entrypoint and policy-using commands.
• Synchronize English/Simplified/Traditional core guidance and document the parser/direct-dict/atomicity limits. Source only: no release, version/tag/v0 update, frozen-research change or external maintainer contact.

Verification

• Reproduced the prior ambiguous-config behavior before implementation; regression log retained locally.
• Full Windows suite: 494 tests, 484 passed and 10 platform skips.
• Linux focused policy JSON suite: 17 passed.
• Wheel and source distribution build passed; all 14 installed-wheel acceptance journeys passed offline.
• Demo remains F 56. These synthetic engineering checks do not establish real-world accuracy, user adoption or policy adequacy.
• Runtime source identity: 3a50ee2add42d2e703bbc8b6816e38b9d82c7fe795993e1b72836ad8cc2a759c.
• Exact-head cross-platform CI and the maintained pinned-repository smoke replay run before merge. An expected operational rejection remains distinct from a clean scan.