fix: preserve dict copy provenance and triage scope

[ApexWorm]

Dict-copy provenance

The Python dict-key detector no longer treats copied mappings as fresh empty dictionaries, preventing false phantom-read findings from dict(source) and dict(**source).

Triage scope

A refreshed triage cycle could be blocked by historical clusters and stale frozen issue IDs. This update scopes organize, enrich, sense-check, runner validation, and confirmations to the live frozen review set. An empty live scope is now distinct from legacy unscoped validation, and strategist output preserves deliberate skipped IDs.

Verification

• Focused dict-key detector tests and real-repository phantom-read validation from the earlier commit
• python3 -m pytest -q tests/commands/plan/test_triage_split_modules_direct.py tests/commands/plan/test_triage_stage_prompts_flow_direct.py tests/commands/plan/test_triage_runner.py tests/commands/plan/test_strategist.py (112 passed)
• Targeted ruff check on changed modules and tests
• git diff --check