fix(mission_runtime): remove ZEROCLAW_WORKSPACE env — it was hijacking config-dir

Deprecated ZEROCLAW_WORKSPACE env var (schema.rs:17467) is used by
the daemon as a legacy config-dir pointer that overrides everything
else. Setting it to /mission/repo made the mission daemon compute
its config dir as /mission/repo/.zeroclaw (empty) and fall back to
defaults — zero agents loaded.

This is the actual root cause of Unknown agent errors on WS. The
seed-mount + admin/paircode/new + per-node-agent-injection fixes
we shipped earlier were correct but couldnt take effect because
the daemon wasnt reading our bind-mounted config at all.

Per-agent workspace pinning belongs in config.toml as
agents.<alias>.workspace, not env.

crates/cm-api/src/mission_runtime.rs

@@ -202,9 +202,17 @@ impl MissionRuntimeProvisioner {
             ..Default::default()
         };
 
+        // NOTE: do NOT set ZEROCLAW_WORKSPACE — despite the name, the
+        // daemon uses it (schema.rs:17467) as a legacy config-dir
+        // pointer that overrides ZEROCLAW_CONFIG_DIR/DATA_DIR. Setting
+        // it to /mission/repo makes the daemon compute its config dir
+        // as /mission/repo/.zeroclaw (empty!) and boot with a fresh
+        // defaults-only config — zero agents loaded.
+        //
+        // Per-agent workspace pinning belongs in the shared config
+        // under agents.<alias>.workspace = "/mission/repo", not env.
         let mut env = vec![
             format!("ZEROCLAW_GATEWAY_PORT={GATEWAY_PORT}"),
-            "ZEROCLAW_WORKSPACE=/mission/repo".to_string(),
             format!("CM_MISSION_ID={mission_id}"),
         ];
         for key in [