docs: add plan to fix broken Go lint baseline

plans/001-fix-broken-go-lint-baseline.md

@@ -0,0 +1,32 @@
+---
+finding: "Fix broken Go lint baseline"
+catalog: "DX / Tooling"
+impact: "The documented full verification gate cannot pass because Go lint currently fails."
+base_commit: "0d31d46"
+---
+
+## Effort
+
+S - one focused refactor plus verification.
+
+## Risk
+
+LOW - the change should preserve behavior and only reduce function complexity.
+
+## Confidence
+
+HIGH - `bun run lint:go` fails reproducibly on one function.
+
+## Evidence
+
+- `internal/observability/fx.go:22` defines `describeFXEventError` with a large type switch.
+- `bun run lint:go` reports `cyclop`: calculated cyclomatic complexity is 11, max is 10.
+- `justfile:40` defines `check` as `lint test typecheck build`, so this failure breaks `just check`.
+
+## Resolution Approach
+
+Refactor `describeFXEventError` without changing the log events it emits. Keep the same public behavior: `LogEvent` should call `describeFXEventError`, ignore events with no error, and log failed Fx lifecycle events with the same event names and field maps.
+
+A small, safe approach is to split the switch into narrower helpers, for example one helper for constructor/invoke/run failures and one helper for lifecycle/start/stop/rollback failures. Another acceptable approach is to use small typed helper functions for repeated return shapes. Do not suppress the linter unless a refactor proves impossible.
+
+Add or update tests if existing tests cover Fx event descriptions. Verify with `bun run lint:go`, then run `go test ./...`. After this lands, `just check` should be able to proceed past Go lint.