chore: disable goconst linter

For log fields and map keys like "reason"/"message", the inline literal is
clearer than a shared constant, and forcing a constant couples unrelated call
sites together. Disable the linter rather than work around it.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01LsQQoiXVgC1VaiWye4eEz8

Author: scotwells

.golangci.yml

@@ -8,7 +8,6 @@ linters:
     - dupl
     - errcheck
     - ginkgolinter
-    - goconst
     - gocyclo
     - govet
     - ineffassign
@@ -37,11 +36,6 @@ linters:
           - dupl
           - lll
         path: internal/*
-      # Repeated string literals in tests are usually fixture/table data;
-      # extracting them to constants hurts readability more than it helps.
-      - linters:
-          - goconst
-        path: _test\.go
       # The validation packages are built almost entirely from field.ErrorList
       # accumulators that hold a handful of errors; preallocating them adds noise
       # without meaningful benefit.