docs: add 39-branch Keycloak governance index

docs/keycloak-branch-index.md

@@ -0,0 +1,29 @@
+# Keycloak branch implementation index
+
+The source inventory contains 39 `feature-keycloak-*.md` branch notes. This
+repository preserves one local Git feature branch for every note and merges it
+with `--no-ff` into either the common `develop` baseline or one of the four
+authentication-pattern branches.
+
+| Target | Meaning |
+|---|---|
+| `common` | Shared realm, federation, deployment, or governance contract. Merge into `develop`, then propagate to AP1–AP4. |
+| `ap1` | Browser-based OAuth client: vanilla SPA, Authorization Code + PKCE, Resource Server. |
+| `ap2` | Token-mediating confidential backend: browser receives access token only. |
+| `ap3` | BFF: backend owns every OAuth token and browser owns only a session cookie. |
+| `ap4` | Edge forward-auth: oauth2-proxy/Nginx owns login and backend trusts an isolated identity header. |
+
+The machine-readable registry is
+[`keycloak-branch-manifest.tsv`](keycloak-branch-manifest.tsv). Run:
+
+```bash
+./scripts/audit-keycloak-branches.sh
+```
+
+The audit succeeds only when all 39 note names have matching local feature
+branches and each feature tip is reachable from its declared target branch.
+
+Google credentials are never committed. The default local acceptance harness
+uses a second Keycloak realm as a controllable OIDC provider so claim mapping
+and unsafe-linking failure paths can be reproduced. A real Google login remains
+an explicit credentialed/public-HTTPS verification profile.

docs/keycloak-branch-manifest.tsv

@@ -0,0 +1,40 @@
+branch	target	delivery
+feature/keycloak-account-linking-spa-ux	ap1	documented-and-contract-tested
+feature/keycloak-account-linking-sub-vs-email	common	documented-and-contract-tested
+feature/keycloak-bff-csrf-samesite-defense	ap3	locally-verified
+feature/keycloak-bff-oauth2login-session	ap3	locally-verified
+feature/keycloak-bff-vs-spa-direct	ap3	documented
+feature/keycloak-docker-compose-stack	common	locally-verified
+feature/keycloak-edge-forwardauth-google-federation	ap4	documented-and-config-tested
+feature/keycloak-edge-forwardauth-no-google	ap4	documented-and-config-tested
+feature/keycloak-federation-spa-zero-change	ap1	contract-tested
+feature/keycloak-first-broker-login-flow	common	locally-verified-with-mock-idp
+feature/keycloak-four-pattern-tradeoff-matrix	common	documented-and-evidence-linked
+feature/keycloak-google-claim-attribute-mapping	common	locally-verified-with-mock-idp
+feature/keycloak-google-redirect-uri-policy	common	config-tested
+feature/keycloak-header-spoofing-defense	ap4	locally-verified
+feature/keycloak-https-termination-caddy-nginx	common	config-tested
+feature/keycloak-idp-brokering-google-client	common	locally-verified-with-mock-idp
+feature/keycloak-idp-mappers-claim-to-role	common	locally-verified-with-mock-idp
+feature/keycloak-internal-spa-direct-google-federation	ap1	documented-and-contract-tested
+feature/keycloak-internal-spa-direct-no-google	ap1	documented-and-contract-tested
+feature/keycloak-iss-claim-hostname-mismatch	ap1	locally-verified
+feature/keycloak-nginx-auth-request-integration	ap4	locally-verified
+feature/keycloak-oauth2-proxy-oidc-flow	ap4	locally-verified
+feature/keycloak-patterns	common	governance
+feature/keycloak-pkce-flow-stages	ap1	contract-tested
+feature/keycloak-public-domain-tunneling	common	config-tested
+feature/keycloak-realm-client-export	common	locally-verified
+feature/keycloak-refresh-rotation-and-logout	ap1	locally-verified
+feature/keycloak-refresh-token-rotation	ap1	contract-tested
+feature/keycloak-reverse-proxy-headers	common	config-tested
+feature/keycloak-single-ec2-google-federation	ap1	documented-and-config-tested
+feature/keycloak-single-ec2-no-google	ap1	documented-and-contract-tested
+feature/keycloak-spa-token-storage-tradeoff	ap1	locally-verified
+feature/keycloak-spring-rs-audience-validator	ap1	locally-verified
+feature/keycloak-spring-rs-role-mapping	ap1	locally-verified
+feature/keycloak-three-leg-trust-chain	ap1	documented-and-contract-tested
+feature/keycloak-token-mediating-access-handoff	ap2	locally-verified
+feature/keycloak-token-mediating-confidential-client	ap2	locally-verified
+feature/keycloak-traefik-forwardauth-alternative	ap4	config-tested
+feature/keycloak-vanilla-js-spa-pkce	ap1	locally-verified