refactor: unify env vars (UWF_HOME, OCAS_HOME) + env only in CLI (#37)

Breaking changes:
- UWF_STORAGE_ROOT → UWF_HOME
- WORKFLOW_STORAGE_ROOT removed (no fallback)
- OCAS_DIR → OCAS_HOME (aligned with ocas CLI)

Library functions no longer read process.env:
- util-agent/storage.ts: resolveStorageRoot(override), getGlobalCasDir(override)
- agent-hermes: isResumeDisabled(flag) pure function, CLI reads env
- agent-claude-code: CLI reads CLAUDE_MODEL and passes to agent

Fixes #37

packages/agent-hermes/src/cli.ts

@@ -1,6 +1,8 @@
 #!/usr/bin/env node
 
 import { createHermesAgent } from "./hermes.js";
+import { isResumeDisabled } from "./session-cache.js";
 
-const main = createHermesAgent();
+const resumeDisabled = isResumeDisabled(process.env.UWF_HERMES_RESUME ?? null);
+const main = createHermesAgent(resumeDisabled);
 void main();