fix(perf): resolve config once in withRepo to avoid double loadConfig

[carlos-alm]

Summary

• withRepo() (backing fn-impact.ts, brief.ts, dependencies.ts, implementations.ts) opens its Repository via openRepo(), which internally resolves config via resolveDbSettings() for engine/busy-timeout selection. Its two callers that also needed analysis-tuning config — fnImpactData via resolveAnalysisOpts(), and briefData via a direct loadConfig() call — triggered a second, independent loadConfig() for the same DB path.
• Beyond the redundant work, that second call resolved its rootDir from process.cwd() instead of the resolved --db path, so --db /other/repo/.codegraph/graph.db would silently read the wrong project's .codegraphrc.json for analysis.fnImpactDepth/analysis.briefCallerDepth — the same correctness gap already fixed for withReadonlyDb()'s callers (exports.ts, context.ts).
• Fix: widen withRepo() to resolve config once and thread it through to both openRepo() (via a new, additive opts.config — every other openRepo() call site is unaffected) and the callback, mirroring withReadonlyDb's (db, config) => T signature. fnImpactData and briefData now reuse opts.config ?? dbConfig instead of calling loadConfig() again.
• dependencies.ts and implementations.ts — the other two withRepo callers — don't read config, so they're unaffected; TypeScript allows their existing (repo) => T callbacks to ignore the new second parameter.

No native/Rust changes: this is a TS-only config-resolution optimization internal to db/connection.ts / domain/analysis/query-helpers.ts orchestration — the native crate has no equivalent concept to mirror.

Fixes #1941

Test plan

• New tests/unit/withrepo-config-resolution.test.ts: spies on loadConfig to assert withRepo, fnImpactData, and briefData each call it exactly once (previously twice for the latter two); also asserts analysis.fnImpactDepth/analysis.briefCallerDepth are read from the --db path's rootDir even when process.cwd() points elsewhere. Verified these tests fail against the pre-fix code (2 loadConfig calls / config not threaded) and pass after the fix.
• npx tsc --noEmit — clean
• npm run lint — clean
• codegraph diff-impact --staged -T — confirms only the intended 5 functions changed (resolveDbSettings, openRepo, briefData, fnImpactData, withRepo), 43 callers across 33 files, all backward-compatible
• npm test — 225/259 files and 3688/4134 tests pass. The remaining 20 failing files (6 individual test failures) all share one root cause unrelated to this change: Cannot find module '@optave/codegraph-darwin-arm64' — this worktree has no built native addon, a pre-existing, already-documented environment gap for isolated worktrees, not something this diff touches.

[greptile-apps]

Greptile Summary

This PR resolves repository config once in the withRepo() path. The main changes are:

• openRepo() can reuse a pre-resolved config for engine and busy-timeout selection.
• withRepo() now passes the DB-path config to both openRepo() and its callback.
• fnImpactData() and briefData() reuse that config instead of loading from process.cwd().
• Regression tests cover single config loading and DB-path-based analysis settings.

Confidence Score: 5/5

This looks safe to merge.

• No blocking issues found in the changed code.
• Existing one-argument withRepo() callbacks remain compatible.
• The new config path keeps normal object overrides working while removing the duplicate cwd-based load.

Important Files Changed

Filename	Overview
src/db/connection.ts	Adds an optional config parameter to the repository-opening path while preserving existing callers.
src/domain/analysis/query-helpers.ts	withRepo() now resolves config once and passes it through to the repository and callback.
src/domain/analysis/fn-impact.ts	fnImpactData() now uses the DB-path config when resolving analysis options.
src/domain/analysis/brief.ts	briefData() now reads analysis config from the config supplied by withRepo().
tests/unit/withrepo-config-resolution.test.ts	Adds tests for the single-load behavior and DB-path config resolution.

_{Reviews (1): Last reviewed commit: "fix(perf): resolve config once in withRe..." | Re-trigger Greptile}

[github-actions]

Codegraph Impact Analysis

5 functions changed → 43 callers affected across 33 files

• resolveDbSettings in src/db/connection.ts:451 (24 transitive callers)
• openRepo in src/db/connection.ts:585 (28 transitive callers)
• briefData in src/domain/analysis/brief.ts:105 (3 transitive callers)
• fnImpactData in src/domain/analysis/fn-impact.ts:265 (2 transitive callers)
• withRepo in src/domain/analysis/query-helpers.ts:38 (21 transitive callers)