inspect: add glob/path filters for targeted profiling

[abegong]

Problem

katalyst inspect can target a path (source layer) or a collection (collection layer), and can narrow by inspector, but it cannot directly narrow the inspected files/items within that target.

For ad-hoc analysis (for example, "inspect all README files"), users currently need a workaround: copy matching files into a temporary directory and run inspect there. That is awkward and easy to skip.

Proposal

Add file/item selection flags to inspect so users can focus analysis without reshaping the corpus.

Potential CLI shape:

katalyst inspect <target> --include "**/README*.md"
katalyst inspect <target> --include "docs/**/*.md" --exclude "**/testdata/**"

Desired behavior

• Support repeatable include globs and optional exclude globs.
• Apply selection before inspectors run.
• Keep evidence denominators explicit (for example, total discovered vs selected).
• Return a clear error/notice when selection matches nothing.

Why this helps

• Removes friction for exploratory profiling.
• Makes common workflows (README-only, docs-only, exclude fixtures) first-class.
• Keeps users in a single command path instead of temporary file staging.