refactor: remove all uncaged codename references

- Remove UNCAGED_CAS_DIR and UNCAGED_WORKFLOW_STORAGE_ROOT env var fallbacks
- Tests updated to use OCAS_DIR / UWF_STORAGE_ROOT
- All docs, READMEs, scripts, workflows, skills updated
- Only symlink migration code retains .uncaged paths (functional requirement)

Closes #12 (Phase 5 complete)

packages/cli/src/__tests__/step-show-json.test.ts

@@ -131,16 +131,16 @@ describe("cmdStepShow JSON serialization", () => {
     testDir = await mkdtemp(join(tmpdir(), "uwf-test-"));
     casDir = join(testDir, "cas");
     await mkdir(casDir, { recursive: true });
-    originalEnv = process.env.UNCAGED_CAS_DIR;
-    process.env.UNCAGED_CAS_DIR = casDir;
+    originalEnv = process.env.OCAS_DIR;
+    process.env.OCAS_DIR = casDir;
   });
 
   afterEach(async () => {
     await rm(testDir, { recursive: true, force: true });
     if (originalEnv === undefined) {
-      delete process.env.UNCAGED_CAS_DIR;
+      delete process.env.OCAS_DIR;
     } else {
-      process.env.UNCAGED_CAS_DIR = originalEnv;
+      process.env.OCAS_DIR = originalEnv;
     }
   });