refactor: group canonical specs by domain and archive account-top-positions (#74)

- Move canonical specs into domain folders (identity, tbank, brokerage,
  portfolio, instruments, banking, frontend-platform, backend-platform).
- Remove process specs; keep still-valid unique rules in openspec/config.yaml.
- Keep project-foundation behavior as app-shell and http-api-foundation.
- Archive account-top-positions without G4 by owner decision (descoped
  review/QA recorded in process-record); sync portfolio-concentration and
  portfolio-view.
- Group AI_INDEX by domain.

Refs: WealthLedger/main#48

openspec/config.yaml

@@ -12,7 +12,15 @@ context: |
   `wealth-ledger-sdd` keep their original proposal → specs → design → tasks → apply
   lifecycle and existing approvals until completion. Never infer approval from
   the existence of an artifact. Schema selection comes from each change's
-  `.openspec.yaml`, not from the current default.
+  `.openspec.yaml`, not from the current default. The Change Owner is the Product
+  Owner for product behavior and the Engineering Owner for technical/process changes.
+  A session handoff never stores requirements, design or tasks and never proves an
+  approval; a new session without an explicitly confirmed approval does not start
+  downstream work. Versioned planning, spec, task and design artifacts live only in
+  `specs/openspec`, never in framework-specific folders elsewhere.
+  Canonical specs are grouped by domain as `specs/<domain>/<capability>/spec.md`;
+  a delta uses the same path. Process rules belong to workspace conventions, this
+  config and schemas, not to canonical specs.
 
   Repository responsibilities and sources of truth:
   - `main` (`./`): workspace instructions, shared configuration, development Compose
@@ -67,3 +75,6 @@ operations:
       - Keep the change's selected schema and explicit approvals; do not impose v2-only artifacts on legacy changes.
       - Complete implementation, developer checks, independent verification and canonical documentation before archive. For v2 changes, also check applicable QA Analysis, docs-impact and target contract compatibility with backend-generated OpenAPI.
       - Native OpenSpec sync/archive updates canonical behavior specs, not implementation documentation.
+      - Independent verification is read-only (no edits to code, specs or tasks) and returns PASS, FAIL or SPEC_ISSUE routed to the earliest affected artifact. For UI changes it compares implemented screens, states, interactions and responsive behavior with the approved visual package.
+      - Archive only after the latest PASS with no Critical or Important findings and no relevant input changes since; archive routes blockers instead of fixing them.
+      - Completion evidence is written after the work and records, per affected repo, the commit, exact commands with observed results, N/A reasons and the review outcome. Never create empty commits to mark an unaffected repo.