feat(analyzer): detect external model selection

[deepujain]

Summary

• add EA5 detection for external model or provider selection
• report top-level SKILL.md frontmatter pins as MEDIUM cost exposure
• report actionable coding-CLI shell-outs as HIGH silent account-switch exposure
• avoid nested/frontmatter defaults, prose-only mentions, language-runtime -m flags, and unknown local model names

Validation

• pytest tests/unit/test_patterns_new.py tests/nodes/analyzers/test_static_patterns.py -q (538 passed)
• pytest -m 'not integration and not provider' tests/ -q (2818 passed, 13 skipped, 38 deselected, 4 xfailed)
• ruff check src tests
• ruff format --check src tests
• real CLI JSON smoke: one HIGH command finding and one MEDIUM frontmatter finding

Risk

• deterministic static analysis only; no provider calls or runtime model changes
• generic model flags require a recognized model family and exclude Python/Node/Perl/Ruby module invocation
• findings are advisory and describe billing/cost exposure rather than malicious intent

Fixes #370

[rng1995]

[SkillSpector Review]

Requesting changes for a HIGH-severity prose false positive. Every inline-code command is classified as actionable regardless of the surrounding sentence, so documentation that merely names a supported CLI command is reported as silent model/account switching. Please require directive or shell-example context for inline code and add descriptive inline-code and fenced-example negative regressions.

[rng1995]

[SkillSpector Maintainer Ping]

@deepujain, thank you for the follow-up commit and thread reply. The new directive-context gate plus descriptive inline-code and fenced-example regressions appear to address the EA5 review feedback. Please resolve the review thread and reply here when you want the updated head re-reviewed.

The branch is currently behind main. GitHub reports it as mergeable with no conflicts, but please update it from main, resolve any conflicts that surface during that update, and keep the required checks green.

[deepujain]

Updated the branch onto current main at 052cd9f, resolved the addressed review thread, and reran the focused EA5/static-pattern suite (542 passed) plus repository-wide Ruff checks. The required GitHub checks are rerunning on the new head. Ready for re-review when convenient.