refactor(cli): rename default data-dir to ./amy and nest MLS state under marmot/

Two on-disk layout changes that only affect freshly-created data-dirs (no
migration shim since `amethyst-cli-data` was never tagged or released):

- Default `--data-dir` is now `./amy` instead of `./amethyst-cli-data` —
  shorter, matches the binary name, and still overridable via the flag or
  `$AMETHYST_CLI_DATA`.
- MLS-only files (`groups/` and `keypackages.bundle`) move under a new
  `marmot/` subdirectory so the top-level root stays tidy as more
  non-Marmot state lands (notes, profile caches, etc). Existing
  top-level files (`identity.json`, `relays.json`, `state.json`) are
  unchanged.

README tree diagram and DEVELOPMENT.md test table updated to match.

cli/DEVELOPMENT.md

@@ -196,7 +196,7 @@ Amy-specific layer still needs its own coverage:
 | Argument parsing (`Args`, flag forms, `--data-dir=…` vs `--data-dir …`) | Plain JVM unit tests in `cli/src/test/kotlin/`. |
 | Error / exit-code contract (bad args → 2, await timeout → 124, runtime → 1) | Table-driven tests invoking `main(argv)` with captured stdout/stderr. |
 | JSON output shape (each command's keys and types) | Snapshot tests: run a command against a throwaway data-dir, assert the JSON matches a golden file. |
-| File layout on disk (`identity.json`, `relays.json`, `groups/*.mls`, `keypackages.bundle`) | Structural assertions after a command sequence. |
+| File layout on disk (`identity.json`, `relays.json`, `marmot/groups/*.mls`, `marmot/keypackages.bundle`) | Structural assertions after a command sequence. |
 | Round-trip between two data-dirs on a local relay | End-to-end shell harnesses under `cli/tests/`. Each harness spins up a local `nostr-rs-relay`, bootstraps two or more fresh identities in their own `--data-dir`s, and drives a scenario via `amy` (+ `wn` for Marmot interop against whitenoise-rs). Today there are two suites: `cli/tests/marmot/` (13 MLS scenarios vs whitenoise-rs) and `cli/tests/dm/` (NIP-17 DM round-trips between two `amy` clients). |
 | Interop with other clients | Covered by `cli/tests/marmot/marmot-interop-headless.sh` (drives Amy against whitenoise-rs `wn`/`wnd`). Add new scenarios there or start a new sibling under `cli/tests/`. |
 

cli/README.md

@@ -40,7 +40,7 @@ What every caller — user, script, agent, CI — can rely on:
 - **Data-dir is the whole world.** All state (identity, relays, MLS
   epochs, message archives, run cursors) lives under `--data-dir PATH`.
   Delete to reset; copy to move; `AMETHYST_CLI_DATA` env var overrides
-  the default `./amethyst-cli-data`.
+  the default `./amy`.
 
 The rationale behind each of these lives in
 [DEVELOPMENT.md](./DEVELOPMENT.md). Breaking any of them is a breaking
@@ -152,7 +152,7 @@ itself crashed".
 
 ### Global flags
 
-- `--data-dir PATH` — defaults to `./amethyst-cli-data` or
+- `--data-dir PATH` — defaults to `./amy` or
   `$AMETHYST_CLI_DATA`. Always an absolute path after resolution.
 - `--help` / `-h` — usage summary.
 
@@ -189,13 +189,14 @@ events.
 
 ```
 <data-dir>/
-├── identity.json         # nsec/npub/hex — the account
+├── identity.json             # nsec/npub/hex — the account
-├── relays.json           # nip65 / inbox / key_package buckets
+├── relays.json               # nip65 / inbox / key_package buckets
-├── state.json            # sync cursors (giftWrapSince, groupSince)
+├── state.json                # sync cursors (giftWrapSince, groupSince)
-├── keypackages.bundle    # MLS KeyPackage bundles (NostrSignerInternal)
+└── marmot/
-└── groups/
+    ├── keypackages.bundle    # MLS KeyPackage bundles (NostrSignerInternal)
-    ├── <gid>.mls         # MLS group state per group
+    └── groups/
-    └── <gid>.log         # decrypted inner events (one JSON per line)
+        ├── <gid>.mls         # MLS group state per group
+        └── <gid>.log         # decrypted inner events (one JSON per line)
 ```
 
 All files are plain JSON or framed binary — human-inspectable, easy to

cli/src/main/kotlin/com/vitorpamplona/amethyst/cli/Config.kt

@@ -132,7 +132,7 @@ data class RunState(
 
 /**
  * Root of the on-disk layout. Any absolute path chosen by `--data-dir` (or
- * `$AMETHYST_CLI_DATA`) — defaults to `./amethyst-cli-data`.
+ * `$AMETHYST_CLI_DATA`) — defaults to `./amy`.
  */
 class DataDir(
     val root: File,
@@ -140,8 +140,9 @@ class DataDir(
     val identityFile = File(root, "identity.json")
     val relaysFile = File(root, "relays.json")
     val stateFile = File(root, "state.json")
-    val groupsDir = File(root, "groups")
+    val marmotDir = File(root, "marmot")
-    val keyPackageBundleFile = File(root, "keypackages.bundle")
+    val groupsDir = File(marmotDir, "groups")
+    val keyPackageBundleFile = File(marmotDir, "keypackages.bundle")
 
     init {
         root.mkdirs()
@@ -169,7 +170,7 @@ class DataDir(
     companion object {
         fun resolve(flag: String?): DataDir {
             val envPath = System.getenv("AMETHYST_CLI_DATA")
-            val path = flag ?: envPath ?: "./amethyst-cli-data"
+            val path = flag ?: envPath ?: "./amy"
             return DataDir(File(path).absoluteFile)
         }
     }