Restructure format_markdown() to show an overview table with linked
function names and file paths, collapsible detailed analysis, and a
suggested fix section. Add helpers for function-name linkification
and root cause extraction from PR attribution text.

Add --suggest CLI flag, Suggestion/SuggestionResult dataclasses, and
generate_suggestions() LLM client that produces actionable source code
fix suggestions from classification results and the PR diff.

Use a stricter regex (_INTERNAL_FUNCTION_PATTERN) that requires
underscores to distinguish pyrefly internal function names like
check_for_imported_final_reassignment() from common Python method
names like get(), match(), set() that appear in error messages.

Asks reviewers to react with 👍 or 👎 so we can track
classifier accuracy over time.

…e display

- Collect error_kinds from both project.added and project.removed so
  improvement-only diffs (all removals) still populate the Error Kinds column
- Add file path fallback in _extract_root_cause when no function name is found
- Add high-level summary paragraph aggregating patterns across projects
- Rename table header from "Error Kind" to "Error Kinds"

…lity

- Change workflow trigger from workflow_dispatch to workflow_run so it
  runs automatically when "Run mypy_primer" completes
- Move feedback prompt out of <sub> tag for better visibility