Stack-Trace Investigator (Meta-Skill)

A combinator-style meta-skill that converts a pasted stack trace into a structured root-cause report. It now classifies Python, JavaScript, TypeScript, Go, Rust, or unknown traces before running the investigation. After parsing the trace once, heterogeneous investigations run in parallel:

1. grep_repo — ripgrep for the symbols in the current repo
2. search_issues — gh issue list for similar reported problems
3. git_history — recent commits touching the affected files
4. diff_context — git-diff skill for current worktree context
5. history_patterns — history-explorer skill for prior skill/router usage patterns
6. memory_recall — prior incidents stored under the traceback topic
7. language_probe — routed to the language-specific helper skill (stack-trace-python-probe, stack-trace-js-probe, stack-trace-go-probe, stack-trace-rust-probe, or generic fallback)