chore(ci,docs): GitHub Actions, ADRs, README overhaul, §21 Hardening Release

- .github/workflows/ci.yml: two jobs — frontend (tsc --noEmit, lint, build,
  Playwright) and backend (Postgres 16 + odoo:19 --test-enable
  --test-tags encoach_api) — catches regressions before merge.
- docs/adr/: start an Architecture Decision Record trail with
  0001 canonical directory layout, 0002 JWT refresh flow,
  0003 paginated response envelope, 0004 RAG metadata + chunking.
- docs/PROJECT_SUMMARY.md §21 Hardening Release: full recap of the AI
  quality loop, compliance, Paymob, i18n, and CI work shipped in this
  drop, plus new DB tables, REST routes, frontend routes, verification
  results, and operator-facing configuration.
- README.md refreshed for the v4 split-repo doctrine and the new feature
  surface.
- new_project/DEPRECATED.md: formal retirement notice pointing at
  backend/ as the canonical tree.

Made-with: Cursor

docs/adr/0000-template.md

@@ -0,0 +1,26 @@
+# ADR {NUMBER}: {TITLE}
+
+- **Status:** Proposed | Accepted | Superseded by ADR-XXXX
+- **Date:** YYYY-MM-DD
+- **Deciders:** @handle1, @handle2
+
+## Context
+
+What is the problem? What forces are at play (technical, business, social)?
+Keep this short; link out to source files or tickets for depth.
+
+## Decision
+
+What did we decide to do? Use imperative voice. Be specific enough that a new
+engineer can understand the scope by reading this section alone.
+
+## Consequences
+
+- Positive: …
+- Negative / trade-offs: …
+- Follow-up work: …
+
+## Alternatives considered
+
+- **Option A** — why it was rejected.
+- **Option B** — why it was rejected.