feat(repo)!: repo reorganization (#16)

* feat(repo)!: restructure around the dsh-harness image and one example per implementation

- the root Dockerfile is the primary artifact; versions.env is the single source of truth
- merge gateway-api/dsh-demo into examples/dsh-agents-as-a-service (manifests/, exposure variants)
- move the single-tenant template into examples/minimal-single-tenant
- publish the gateway as a nested package under the repository image
- mirror the DSH ref for release identities (first release dsh-v0.2.1-rc.2-r2)
- CI: lint/python/manifests/gateway-image, reusable multi-arch build, tag-driven release, weekly e2e
- docs: README, docs/{main-image,examples,gitflow,versioning}, example READMEs, AGENTS.md, governance
- SSO is opt-in again; gateway pull policy and cookie defaults match the documented demo

BREAKING CHANGE: example manifest paths, the gateway image name, and the removal
of deploy/ and gateway-api/ affect existing deployments; see the migration table
in README.md.

* docs(changelog): generate initial changelog from history

* fix(scripts): make set-version update Dockerfile and sample revision pins

* build(hadolint): document intentional lint exceptions for the main image

---------

Co-authored-by: SREDevOpsAgents <agents@sredevops.org>

.lychee.toml

@@ -0,0 +1,13 @@
+# Link checker for README/docs. Placeholders used by the examples are excluded
+# on purpose; real URLs must resolve.
+verbose = "info"
+no_progress = true
+max_retries = 2
+exclude = [
+  "localhost",
+  "127\\.0\\.0\\.1",
+  "example\\.com",
+  "your-github-org",
+  "mailto:",
+  "ghcr\\.io/.*@sha256",
+]