Wave 4c: Result formatting and output

[dean0x]

Overview

Format compound search results for terminal and JSON output.

Module: crates/rskim-search/src/compound/output.rs (~200 lines)

Terminal format

```
src/auth/handler.rs:42 [0.87] FunctionSignature
pub async fn handle_auth(req: AuthRequest) -> Result { /* ... */ }

src/models/user.rs:15 [0.72] TypeDefinition
pub struct AuthRequest { ... }
```

JSON format

Valid JSON array with all fields: file_path, line, score, field, snippet, layers_matched.

Dependencies

• Tech debt: token budget cascade follow-ups #28 (ranking)

Acceptance Criteria

• Terminal output readable with metadata
• JSON output valid and complete
• Respects --limit flag
• Follows output patterns from existing rskim output modules

Implementation Guidelines Checklist

• No file exceeds 400 lines
• Every public function has /// doc comment
• Module has #[cfg(test)] mod tests

---

Wave 3g (#199) follow-up:

#199 ships file-level AST-only output (matched pattern name + description + file path + AST score; no line numbers). Precise line spans require re-parsing each matched file because the AST index is file-level (no stored line offsets). #201 should add the line-span re-parse to produce per-match line numbers/snippets for AST-only results.

[dean0x]

Wave 3g (#199, PR #291) interim note — AST output is file-level only; line spans deferred here.

Standalone --ast results are emitted at file granularity: a pattern name + description header then path score lines, with no line numbers (typed --json: {mode:"ast",pattern,description,total,results:[{path,score}]}). The AST index stores n-grams per file, not source spans, so there is no per-match location to print yet.

Wave 4c (this issue) owns line-span formatting for structural matches — resolving a matched pattern back to the node's source range so --ast output can show the offending line(s) like lexical results do. (Text+AST intersection already shows full lexical snippets because it reuses the lexical formatters.)

[dean0x]

Resolved on wave/wave4-search (Wave-4 compound engine + AST/temporal follow-ups). Tracked in North Star #174. Not yet on main — ships with PR #368 (wave→main).