refactor: unify impact-level rendering format between audit and fn-impact commands

[carlos-alm]

Summary

BEHAVIOR CHANGE: codegraph audit's impact-level text output now matches fn-impact's icon+truncation format, per this issue's own recommendation.

• renderAuditFunction (audit.ts) and printFnImpactLevels (queries-cli/impact.ts) duplicated impact-level rendering with different formats: audit.ts's was plain-text/unlimited, impact.ts's had icons/file:line/truncation-at-20.
• Investigated downstream dependencies before changing anything: no test asserts on the old text format (only --json output is tested at the CLI level), no .claude/skills/hooks parse the plain-text format (all pass --json), and both call sites already source levels from the same bfsTransitiveCallers function so name/kind/file/line are always populated identically — no data-shape gap to handle.
• Extracted renderImpactLevels(levels, opts) (new src/presentation/impact-levels.ts) using the richer fn-impact format as canonical; adopted in both call sites, removing printFnImpactLevels entirely.

Closes #1756

Test plan

• npm test — full suite green (3519 passed, 0 failed), zero test updates needed since nothing asserted on the old format
• npm run lint / npm run typecheck — clean
• Manual: codegraph audit <fn> -T and codegraph fn-impact <fn> -T against this repo's own graph now render impact levels identically; zero-impact case correctly preserves each command's existing empty-state convention (audit suppresses, fn-impact shows "No callers found.")

Filed #1873 for a pre-existing, unrelated finding: docs/examples/CLI.md/MCP.md's audit/diff-impact example output blocks are already stale relative to the current implementation.

Stacked on #1872 (base branch fix/issue-1755-leiden-deltamod-directed-complexity) — only the presentation diff is this issue's change.

[greptile-apps]

Greptile Summary

This PR extracts the duplicated impact-level rendering logic from audit.ts and queries-cli/impact.ts into a new shared module src/presentation/impact-levels.ts, making the two commands' text output visually identical. The audit command now renders impact levels with icons, file:line references, and per-level truncation rather than the former plain comma-joined names.

• New renderImpactLevels(levels, opts) in impact-levels.ts is the canonical renderer; opts.emptyMessage (defaulting to " No callers found.") and opts.limit (default 20) give callers the flexibility to preserve each command's existing empty-state convention.
• printFnImpactLevels is deleted from impact.ts; both call sites now delegate to the shared function.
• The emptyMessage !== null guard (strict null check) correctly honours the documented null-means-silent contract, and the default sort by numeric level key matches the old behaviour.

Confidence Score: 5/5

Safe to merge — the change is a straightforward extraction of duplicated rendering logic into a well-typed shared module with no behavioural surprises.

Both call sites are updated consistently, the strict-null guard on emptyMessage correctly honours the documented contract, the sort and truncation logic are faithful copies of the deleted function, and the typecheck + full test suite pass cleanly with zero test changes needed.

No files require special attention.

Important Files Changed

Filename	Overview
src/presentation/impact-levels.ts	New shared renderer; correct strict-null guard, configurable limit/emptyMessage, and level-sorted iteration identical to the removed printFnImpactLevels.
src/presentation/audit.ts	renderImpactSection now delegates to renderImpactLevels with emptyMessage:null, correctly suppressing the empty-state line that the count line above already communicates.
src/presentation/queries-cli/impact.ts	printFnImpactLevels removed; fnImpact now calls renderImpactLevels with default opts, preserving the original "No callers found." empty-state message.

Flowchart

%%{init: {'theme': 'neutral'}}%%
flowchart TD
    A["codegraph audit"] -->|"renderImpactSection(fn)"| C
    B["codegraph fn-impact"] -->|"fnImpact(name, ...)"| D

    C["renderImpactLevels(fn.impact.levels,\n{ emptyMessage: null })"]
    D["renderImpactLevels(r.levels)\n(emptyMessage defaults to 'No callers found.')"]

    C --> E["impact-levels.ts\nrenderImpactLevels(levels, opts)"]
    D --> E

    E --> F{levels empty?}
    F -->|yes + emptyMessage !== null| G["console.log(emptyMessage)"]
    F -->|yes + emptyMessage === null| H["(silent)"]
    F -->|no| I["sort by numeric level\nfor each level: print header + up to limit entries\n+ truncation notice if needed"]

Loading

%%{init: {'theme': 'base', 'themeVariables': {"darkMode": true, "background": "#0d1117", "primaryColor": "#21262d", "primaryTextColor": "#e6edf3", "primaryBorderColor": "#8b949e", "lineColor": "#8b949e", "textColor": "#e6edf3", "edgeLabelBackground": "#161b22", "actorBkg": "#21262d", "actorBorder": "#8b949e", "actorTextColor": "#e6edf3", "actorLineColor": "#8b949e", "signalColor": "#8b949e", "signalTextColor": "#e6edf3", "noteBkgColor": "#373320", "noteBorderColor": "#d4a72c", "noteTextColor": "#f0e6c0", "labelBoxBkgColor": "#21262d", "labelBoxBorderColor": "#8b949e", "labelTextColor": "#e6edf3", "loopTextColor": "#e6edf3", "activationBkgColor": "#30363d", "activationBorderColor": "#8b949e"}}}%%
flowchart TD
    A["codegraph audit"] -->|"renderImpactSection(fn)"| C
    B["codegraph fn-impact"] -->|"fnImpact(name, ...)"| D

    C["renderImpactLevels(fn.impact.levels,\n{ emptyMessage: null })"]
    D["renderImpactLevels(r.levels)\n(emptyMessage defaults to 'No callers found.')"]

    C --> E["impact-levels.ts\nrenderImpactLevels(levels, opts)"]
    D --> E

    E --> F{levels empty?}
    F -->|yes + emptyMessage !== null| G["console.log(emptyMessage)"]
    F -->|yes + emptyMessage === null| H["(silent)"]
    F -->|no| I["sort by numeric level\nfor each level: print header + up to limit entries\n+ truncation notice if needed"]

Loading

_{Reviews (3): Last reviewed commit: "fix: use strict null check for emptyMess..." | Re-trigger Greptile}

[github-actions]

Codegraph Impact Analysis

9 functions changed → 6 callers affected across 4 files

• renderImpactSection in src/presentation/audit.ts:67 (3 transitive callers)
• ImpactLevelRef.name in src/presentation/impact-levels.ts:14 (0 transitive callers)
• ImpactLevelRef.kind in src/presentation/impact-levels.ts:15 (0 transitive callers)
• ImpactLevelRef.file in src/presentation/impact-levels.ts:16 (0 transitive callers)
• ImpactLevelRef.line in src/presentation/impact-levels.ts:17 (0 transitive callers)
• RenderImpactLevelsOpts.emptyMessage in src/presentation/impact-levels.ts:26 (0 transitive callers)
• RenderImpactLevelsOpts.limit in src/presentation/impact-levels.ts:28 (0 transitive callers)
• renderImpactLevels in src/presentation/impact-levels.ts:41 (5 transitive callers)
• fnImpact in src/presentation/queries-cli/impact.ts:232 (1 transitive callers)

[carlos-alm]

@greptileai

[carlos-alm]

Recreated as #1931 — this PR was inadvertently closed when its stacked base branch was deleted after #1925 merged. Continuing there.