Initial scaffold: API service, K8s operator, and CRDs

Forgebot is a K8s operator + API service for dispatching AI agent
jobs from git forge commands. Includes:

- CRDs: AgentPool, AgentTask, ProviderQueue, RepositoryBinding
- API server with webhook handler, task queue, and comment proxy
- Operator controllers for task scheduling and job management
- Gitea provider with webhook parsing and signature verification
- PostgreSQL database with auto-migration
- Woodpecker CI pipelines and multi-stage Dockerfiles

config/samples/agenttask.yaml

@@ -0,0 +1,17 @@
+---
+apiVersion: forgebot.unkin.net/v1alpha1
+kind: AgentTask
+metadata:
+  name: example-review
+  namespace: forgebot
+spec:
+  poolRef: default-pool
+  command: review
+  skill: review
+  repository: unkin/artifactapi
+  ref: refs/pull/42/head
+  context:
+    prNumber: 42
+    commentID: 12345
+    body: "/review check for security issues"
+    author: unkinben