feat: encrypted vault keystore, JWT auth, Drive upload

Vault keystore (vault_keystore.rs):
- AES-256-GCM encrypted local storage for root tokens + unseal keys
- Argon2id KDF with machine-specific salt, 0600 permissions
- save/load/verify/export API with 26 unit tests
- Integrated into seed flow: save after init, load as fallback,
  backfill from cluster, restore K8s Secret if wiped

Vault CLI:
- vault reinit: wipe and re-initialize vault with confirmation
- vault keys: show local keystore status
- vault export-keys: plaintext export for machine migration
- vault status: now shows keystore status + uses JWT auth
- Fixed seal_status() bypassing request() (missing auth headers)

Vault OIDC auth:
- JWT auth method enabled on OpenBao via seed script
- cli-admin role: full access for users with admin:true JWT claim
- cli-reader role: read-only for non-admin SSO users
- BaoClient.with_proxy_auth(): sends both Bearer (proxy) and
  X-Vault-Token (vault) headers
- SunbeamClient.bao() authenticates via JWT login, falls back
  to local keystore root token

Drive:
- SDK client uses /items/ endpoint (was /files/ and /folders/)
- Added create_child, upload_ended, upload_to_s3 methods
- Added recursive drive upload command (--path, --folder-id)
- Switched all La Suite clients to /external_api/v1.0/

Infrastructure:
- Removed openbao-keys-placeholder.yaml from kustomization
- Added sunbeam.dev/managed-by label to programmatic secrets
- kv_patch→kv_put fallback for fresh vault initialization
- Hydra/Kratos secrets combined (new,old) for key rotation

Cargo.lock

@@ -146,6 +146,18 @@ dependencies = [
  "object",
 ]
 
+[[package]]
+name = "argon2"
+version = "0.5.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3c3610892ee6e0cbce8ae2700349fcf8f98adb0dbfbee85aec3c9179d29cc072"
+dependencies = [
+ "base64ct",
+ "blake2",
+ "cpufeatures",
+ "password-hash",
+]
+
 [[package]]
 name = "asn1-rs"
 version = "0.7.1"
@@ -323,6 +335,15 @@ dependencies = [
  "serde_core",
 ]
 
+[[package]]
+name = "blake2"
+version = "0.10.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "46502ad458c9a52b69d4d4d32775c788b7a1b85e8bc9d482d92250fc0e3f8efe"
+dependencies = [
+ "digest",
+]
+
 [[package]]
 name = "block-buffer"
 version = "0.10.4"
@@ -2269,6 +2290,17 @@ dependencies = [
  "windows-link",
 ]
 
+[[package]]
+name = "password-hash"
+version = "0.5.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "346f04948ba92c43e8469c1ee6736c7563d71012b17d40745260fe106aac2166"
+dependencies = [
+ "base64ct",
+ "rand_core 0.6.4",
+ "subtle",
+]
+
 [[package]]
 name = "pbkdf2"
 version = "0.12.2"
@@ -3484,6 +3516,8 @@ dependencies = [
 name = "sunbeam-sdk"
 version = "1.0.1"
 dependencies = [
+ "aes-gcm",
+ "argon2",
  "base64",
  "bytes",
  "chrono",