feat(cli): add --workspace filter to 'dispatch list'

The backend already supported GET /conversations?workspaceId= but the CLI
never sent it. Wire the list command to that filter:

- args.ts: parse --workspace / -w on 'list' (placed before the --catch-all
  so the single-dash -w shorthand isn't taken for a positional prefix);
  add workspaceId? to the list ParsedCommand.
- http.ts: add workspaceId? to FetchConversationsOpts; send ?workspaceId=
  (after q/status, preserving URLSearchParams order).
- main.ts: forward parsed.workspaceId into fetchConversations; update USAGE.

Composable with --status and the <prefix> short-id arg. 'Open conversations
in workspace X' is now: dispatch list --workspace X  (status defaults to
active,idle). No contract changes — purely additive CLI wiring.

Tests: +4 args (incl. composability + missing-value error), +2 http
(exact ?workspaceId= URL + combined status/workspaceId with %2C encoding).
typecheck EXIT 0, biome clean (364 files), full suite 1558 passed.
Live-verified against an isolated server.

1 files changed, 6 insertions, 0 deletions

diff --git a/packages/cli/src/args.ts b/packages/cli/src/args.ts
index aaad2de..74cc56a 100644
--- a/packages/cli/src/args.ts
+++ b/packages/cli/src/args.ts
@@ -33,6 +33,7 @@ export type ParsedCommand =
 			readonly server: string;
 			readonly query?: string;
 			readonly status?: string;
+			readonly workspaceId?: string;
 			readonly all: boolean;
 	  }
 	| { readonly kind: "compact"; readonly server: string; readonly conversationId: string }
@@ -85,6 +86,7 @@ export function parseArgs(argv: readonly string[], opts: ParseOpts): ParsedComma
 		let server = opts.defaultServer;
 		let query: string | undefined;
 		let status: string | undefined;
+		let workspaceId: string | undefined;
 		let all = false;
 		for (let i = 1; i < argv.length; i++) {
 			const arg = argv[i] as string;
@@ -94,6 +96,9 @@ export function parseArgs(argv: readonly string[], opts: ParseOpts): ParsedComma
 			} else if (arg === "--status") {
 				if (i + 1 >= argv.length) return { kind: "error", message: "--status requires a value" };
 				status = argv[++i];
+			} else if (arg === "--workspace" || arg === "-w") {
+				if (i + 1 >= argv.length) return { kind: "error", message: "--workspace requires a value" };
+				workspaceId = argv[++i];
 			} else if (arg === "--all") {
 				all = true;
 			} else if (arg.startsWith("--")) {
@@ -109,6 +114,7 @@ export function parseArgs(argv: readonly string[], opts: ParseOpts): ParsedComma
 			server,
 			...(query !== undefined && { query }),
 			...(status !== undefined && { status }),
+			...(workspaceId !== undefined && { workspaceId }),
 			all,
 		};
 	}