Add golangci-lint config and lint tasks

- Add .golangci.yml with sensible defaults for the project
- Add lint and lint:fix tasks to Taskfile
- Remove unused findGitRoot function
- Apply gofumpt formatting fixes

.golangci.yml

@@ -0,0 +1,64 @@
+version: "2"
+
+linters:
+  default: standard
+  enable:
+    - errcheck
+    - govet
+    - staticcheck
+    - unused
+    - ineffassign
+    - misspell
+    - unconvert
+    - unparam
+    - gosec
+    - prealloc
+    - revive
+    - gocritic
+    - errname
+    - errorlint
+    - nilerr
+    - bodyclose
+    - durationcheck
+    - exhaustive
+    - copyloopvar
+    - perfsprint
+    - usestdlibvars
+  disable:
+    - depguard
+    - funlen
+    - gochecknoglobals
+    - gochecknoinits
+    - lll
+    - wsl
+    - nlreturn
+    - varnamelen
+    - exhaustruct
+    - ireturn
+    - nonamedreturns
+
+  exclusions:
+    generated: lax
+    presets:
+      - comments
+      - std-error-handling
+      - common-false-positives
+    rules:
+      - path: _test\.go
+        linters:
+          - errcheck
+          - gosec
+          - dupl
+
+formatters:
+  enable:
+    - gofumpt
+    - goimports
+
+issues:
+  max-issues-per-linter: 50
+  max-same-issues: 3
+
+run:
+  timeout: 5m
+  tests: true

Taskfile.yml

@@ -69,6 +69,16 @@ tasks:
     cmds:
       - go mod tidy
 
+  lint:
+    desc: Run golangci-lint
+    cmds:
+      - golangci-lint run
+
+  lint:fix:
+    desc: Run golangci-lint with auto-fix
+    cmds:
+      - golangci-lint run --fix
+
   clean:
     desc: Remove built binary
     cmds:

main.go

@@ -105,7 +105,8 @@ func formatContextInfo(contextSize int, usage *struct {
 	InputTokens          int `json:"input_tokens"`
 	CacheCreationTokens  int `json:"cache_creation_input_tokens"`
 	CacheReadInputTokens int `json:"cache_read_input_tokens"`
-}) string {
+},
+) string {
 	totalK := contextSize / 1000
 
 	if usage == nil {
@@ -177,19 +178,6 @@ func getGitInfo(cwd string) string {
 	return fmt.Sprintf(" git:(%s)", branch)
 }
 
-func findGitRoot(path string) string {
-	for {
-		if _, err := os.Stat(filepath.Join(path, ".git")); err == nil {
-			return path
-		}
-		parent := filepath.Dir(path)
-		if parent == path {
-			return ""
-		}
-		path = parent
-	}
-}
-
 func getTerminalWidth() int {
 	ws, err := unix.IoctlGetWinsize(int(os.Stdout.Fd()), unix.TIOCGWINSZ)
 	if err != nil {