Move the source roots, file types and input exclusions from lint_scope.py
into policy/common.json. Keep the existing scope, including KUnit sources,
the newer QLogic target and the exclusions for the legacy QLogic tree,
upstream QLogic sources, compiler probes and generated module metadata.
Adapt engine's reviewed-data and strict-loader approach to SCST. Require
reasons for input exclusions and reject malformed, missing or ambiguous
policy before selecting files. Do not import engine's exclusions or add
environment-based filtering or diagnostic suppression.
Use this policy for full, diff and explicit-file selection. Preserve both
lexical and resolved path checks, single-commit diff bases and index-based
selection. Treat policy paths literally in Git pathspecs as well as Python.
Add isolated fixtures for schema failures and policy-driven selection.
