Complete fin-hub repo integration (FIN-WP-0000)

Link the DB-first onboarding workstream to FIN-WP-0000-repo-integration.md,
finish agent orientation (rules stubs, remove first-session), add repo
classification, and close all four custodian onboarding tasks.

.repo-classification.yaml

@@ -0,0 +1,24 @@
+# Repo classification (Repo Classification Standard v1.0).
+
+repo_classification:
+  standard: Repo Classification Standard
+  version: '1.0'
+  classified_at: '2026-07-08'
+  classified_by: human
+  category: tooling
+  domain: infotech
+  secondary_domains:
+  - financials
+  capability_tags:
+  - platform
+  - observability
+  - orchestration
+  business_stake:
+  - technology
+  - execution
+  - operations
+  business_mechanics:
+  - operation
+  - control
+  notes: Financial Allocator hub for the FOS federation — budgets, burn rate,
+    runway projection, and cross-hub viability signals. product-as-component.