Merge the three repositories into one monorepo

nisse-core's history becomes the repo root; the spec moves to docs/ at
top level; nisse-dev and nisse-ops fold in as package directories, their
seed histories (pointer files only) discarded. Pointer READMEs and
CLAUDE.mds are rewritten for in-tree paths.

Rationale: for a solo operator the three-repo split tripled admin
surface (tokens, CI, webhooks, permissions, backups) and imposed a
version-pinning contract on nisse-core, while the repo boundary was
never a trust boundary — the VM is. The spec's Part H is updated in the
next commit to record the decision.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

nisse-ops/CLAUDE.md

@@ -0,0 +1,10 @@
+# nisse-ops
+
+The Sysadmin Agent (Part C of the Nisse system). A thin application over the shared
+`nisse-core` package.
+
+**Read the architecture before making design decisions here:**
+`docs/Architecture-Build-Spec.md` at the repo root. Part C specifies this agent;
+Part A specifies the library contracts it depends on. Requirements that look like
+free choices in this package — the permission policy engine, confirm-first gating,
+secrets and SSO handling — are usually settled there.

nisse-ops/README.md

@@ -0,0 +1,8 @@
+# nisse-ops
+
+The Sysadmin Agent: operates and maintains infrastructure, driven by Vikunja
+tickets, gated on high-consequence actions. A thin application over the shared
+`nisse-core` library. Built after the Dev Agent works.
+
+**Part C** of the specification at [`../docs/Architecture-Build-Spec.md`](../docs/Architecture-Build-Spec.md)
+covers this agent; **Part A** covers the library it sits on.