feat: Spring Boot config files in repos

application*.properties/.yml and bootstrap* files tracked by git are
listed under Repos, with their secret-looking keys as secrets.

- Keys whose name ends like a secret (password, secret, token, key, …)
  or whose value looks like one (Jasypt ENC(...), a URL or connection
  string with a password) are listed; providers.repos.spring.keys and
  .values replace the patterns, also in a repo's .lazysecrets.yaml.
- A file's details count the keys left out; ${VAR} values are marked
  as references, and a tracked file is only marked red when a listed
  value is in plain text.
- Later YAML/properties documents name their keys after the profile:
  spring.datasource.password (prod).
- Maven's @placeholders@ parse; Argo CD's applications.yaml and Helm
  templates aren't Spring files.
- A green leaf icon, themeable with springColor.

internal/ui/styles/styles.go

@@ -34,6 +34,7 @@ type Styles struct {
 	KindAzure      lipgloss.Style
 	KindDatabricks lipgloss.Style
 	KindRepo       lipgloss.Style
+	Spring         lipgloss.Style // Spring Boot config files
 
 	// themed marks the selection colours as set by the theme, so
 	// OnBackground leaves them.
@@ -70,6 +71,7 @@ func Default() Styles {
 		KindAzure:      lipgloss.NewStyle().Foreground(lipgloss.Blue),
 		KindDatabricks: lipgloss.NewStyle().Foreground(lipgloss.Red),
 		KindRepo:       lipgloss.NewStyle().Foreground(lipgloss.Magenta),
+		Spring:         lipgloss.NewStyle().Foreground(lipgloss.Green),
 	}
 }