feat: add export/import commands for batch backup (JSON/TOML/YAML)

- export: filter by namespace/kind/name/tag/query, decrypt secrets, write to file or stdout
- import: parse file, conflict check (error by default, --force to overwrite), --dry-run preview
- Add ExportFormat enum, ExportData/ExportEntry in models.rs with TOML↔JSON conversion
- Bump version to 0.9.0

Made-with: Cursor

Cargo.lock

@@ -1836,7 +1836,7 @@ checksum = "94143f37725109f92c262ed2cf5e59bce7498c01bcc1502d7b9afe439a4e9f49"
 
 [[package]]
 name = "secrets"
-version = "0.8.0"
+version = "0.9.0"
 dependencies = [
  "aes-gcm",
  "anyhow",
@@ -1853,6 +1853,7 @@ dependencies = [
  "semver",
  "serde",
  "serde_json",
+ "serde_yaml",
  "sha2",
  "sqlx",
  "tar",
@@ -1982,6 +1983,19 @@ dependencies = [
  "serde",
 ]
 
+[[package]]
+name = "serde_yaml"
+version = "0.9.34+deprecated"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6a8b1a1a2ebf674015cc02edccce75287f1a0130d394307b36743c2f5d504b47"
+dependencies = [
+ "indexmap",
+ "itoa",
+ "ryu",
+ "serde",
+ "unsafe-libyaml",
+]
+
 [[package]]
 name = "sha1"
 version = "0.10.6"
@@ -2681,6 +2695,12 @@ dependencies = [
  "subtle",
 ]
 
+[[package]]
+name = "unsafe-libyaml"
+version = "0.2.11"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "673aac59facbab8a9007c7f6108d11f63b603f7cabff99fabf650fea5c32b861"
+
 [[package]]
 name = "untrusted"
 version = "0.9.0"