feat(properties): add parent_id for sub-property hierarchy

Phase 1 of the parent/child rollup feature. Self-FK on properties
with ON DELETE RESTRICT, plus a CHECK that blocks self-reference at
the DB level. Service-layer helpers (getDescendantIds,
getAncestorIds, assertNoCycle) walk the tree via recursive CTEs and
guard against cycles and cross-company parents. softDeleteProperty
now refuses to delete a property with live children.

No UI yet — readers and roll-up routes land in Phase 2.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

drizzle/meta/_journal.json

@@ -113,6 +113,20 @@
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       "tag": "0015_expenses_updated_at_trigger",
       "breakpoints": true
+    },
+    {
+      "idx": 16,
+      "version": "7",
+      "when": 1777268853483,
+      "tag": "0016_property_parent_id",
+      "breakpoints": true
+    },
+    {
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+      "version": "7",
+      "when": 1777268853484,
+      "tag": "0017_property_parent_check",
+      "breakpoints": true
     }
   ]
 }