REQ-041: ORCA_HOME is now the single namespace root for all components
(db, certs, init, daemon). store.Open("") and init command both
route through certpaths.Dir()/DBPath() instead of hardcoding ~/.orca.
Backward compatible: empty ORCA_HOME -> ~/.orca.
REQ-042: --system persistent flag on rootCmd sets ORCA_HOME=/root/.orca
via PersistentPreRunE. Errors on conflict with pre-set ORCA_HOME.
Tests: 7 new tests in namespace_test.go (default, ORCA_HOME override,
--system sets root, conflict detection, init --json, flag registered).
Full suite passes (no regressions).
Docs: docs/namespace.md covers default, ORCA_HOME, --system, ORCA_DB,
resolution order, and path layout tables.
---ci---
project: orca
phase: 1
milestone: v0.5
status: verify
---/ci---
Jon Chery
4bfc246be4