docs(mcp): document login-pending.json in the README (WALM-647)

packages/mcp/README.md

@@ -55,6 +55,8 @@ Use CLI flags or environment variables to override the default Walrus Memory end
 
 Enable verbose stderr logging with `MEMWAL_MCP_DEBUG=1`.
 
+Set `MEMWAL_MCP_TRANSPORT=http` to dial the relayer's Streamable HTTP endpoint instead of the default SSE pair. Opt-in: reconnect replay is not transport-aware yet, so a write interrupted mid-send may be retried and duplicated.
+
 ## Default Namespace
 
 By default the MCP tool schemas expose an optional `namespace` argument and the
@@ -152,6 +154,17 @@ Credentials are stored locally in `~/.memwal/credentials.json`. To remove them:
 npx -y @mysten-incubation/memwal-mcp --logout
 ```
 
+A sign-in that is still in flight also writes a `login-pending.json`
+write-ahead record, beside `credentials.json` in `~/.memwal`. It holds the
+delegate keypair minted for that sign-in, written before the browser can
+register the public half on-chain so an interrupted login can be reclaimed
+instead of paid for a second time. Same owner-only mode `0600` as
+`credentials.json`.
+
+It is removed once the sign-in completes, on `--logout`, and on a successful
+recovery at the next start. A record older than 24 hours is discarded rather
+than reused.
+
 ### Per-project credentials
 
 A project can keep its own `.memwal/credentials.json` so memory written from it
@@ -175,19 +188,21 @@ outside the repository, so a repository cannot carry its own approval.
 Approving also picks the file that is **written**: a later sign-in from that
 project saves a delegate private key into `.memwal/credentials.json` in plain
 text, inside the repository. `approve-project` says so, and so does the sign-in
-warning. Add `.memwal/` to your `.gitignore`. (The short-lived login
-write-ahead record is kept outside the repository either way.)
-
-`MEMWAL_CREDS_DIR` points both the credentials and the approval record at a
-directory of your choosing and overrides project resolution entirely, with no
-approval. Because it skips the gate, it must be an **absolute path outside the
-current project**: a relative value would resolve against the working directory
-and put the approval record inside the repository, and an MCP client passes on
-the `env` block it reads from `.cursor/mcp.json` / `.vscode/mcp.json` /
-`.claude/settings.json` in the checkout — where `${workspaceFolder}` is expanded,
-so an in-project absolute path is not proof you chose it. Anything else is
-refused with an error naming the value, rather than quietly ignored. An empty
-value means unset.
+warning. Add `.memwal/` to your `.gitignore`. The write-ahead record is the one
+thing that stays out: a project sign-in keeps it in `~/.memwal/login-pending/`,
+one file per approved project, so no key material lands in the checkout and a
+sign-in is still reclaimable only by the project that started it.
+
+`MEMWAL_CREDS_DIR` points the credentials, the approval record and the
+write-ahead record at a directory of your choosing and overrides project
+resolution entirely, with no approval. Because it skips the gate, it must be an
+**absolute path outside the current project**: a relative value would resolve
+against the working directory and put the approval record inside the
+repository, and an MCP client passes on the `env` block it reads from
+`.cursor/mcp.json` / `.vscode/mcp.json` / `.claude/settings.json` in the
+checkout — where `${workspaceFolder}` is expanded, so an in-project absolute
+path is not proof you chose it. Anything else is refused with an error naming
+the value, rather than quietly ignored. An empty value means unset.
 
 `memwal_health` reports the destination in use as `account=… relayer=…`.