docs(P03): full-stack examples — 5 jobspecs + rendered artifacts + walkthrough

P03 — full-stack example with ingress configured (REQ-094; gate C-20).

examples/full-stack/:
- web-app.md: kind Service, process runtime, 3 replicas, Unix socket
  (default R-007), rolling update, constraints (node.role==web),
  affinity (zone==a weight 80), lifecycle hooks (post_start/pre_stop).
- api.md: kind Service, process runtime, 2 replicas, TCP opt-in
  (service.bind: 127.0.0.1, R-007), canary update with manual promote,
  constraints (node.role==api, node.cpus>=2), env vars.
- worker.md: kind Job, process runtime, one-shot, timeout 300s, env
  vars, lifecycle hooks (register/drain).
- log-shipper.md: kind Service (DaemonSet workaround — parser gap),
  process runtime, constraints (node.role==logs), env vars. Notes the
  v0.9 parser gap (schedule: block not wired) in a callout.
- postgres.md: kind Service, process runtime, 1 replica, blue-green
  update, volumes with replication (replicate:peer-b,peer-c via
  Syncthing), constraints (node.role==db, node.cpus>=4, node.memory>=8192).
- rendered/: Traefik dynamic YAML (web-app, api) + systemd units
  (web-app, api, log-shipper) showing what Orca generates on target nodes.
- README.md: end-to-end walkthrough (init -> node join -> capacity set
  -> ns create -> job run -> list --watch -> inspect rendered -> verify
  ingress -> drain/rollback). Cross-links to docs/ingress.md.
- examples_test.go: Go test that parses + validates all 5 jobspecs
  against the current parser and schema validators (gate C-20).

All 5 jobspecs pass jobspec.ParseFile + schema.ValidatorFor(kind).

---ci---
project: orca
phase: 3
milestone: v0.10
status: execute
---/ci---

examples/full-stack/rendered/systemd-api.service

@@ -0,0 +1,9 @@
+# Systemd unit for orca api service (alloc api-0)
+# Generated by SystemdEmitter (internal/emitter/systemd.go)
+# Path on target node: /etc/systemd/system/orca-v1-api.service
+# service.bind: 127.0.0.1 (TCP opt-in, R-007)
+[Service]
+ExecStart=/usr/bin/api-server --listen 127.0.0.1:9090
+RuntimeDirectory=orca/alloc-api-0
+# socket: /run/orca/alloc-api-0/port-api.sock
+ExecStartPre=/bin/echo orca: bind 127.0.0.1 port api (tcp, R-007 opt-in)

examples/full-stack/rendered/systemd-log-shipper.service

@@ -0,0 +1,7 @@
+# Systemd unit for orca log-shipper service
+# Generated by SystemdEmitter (internal/emitter/systemd.go)
+# Path on target node: /etc/systemd/system/orca-v1-log-shipper.service
+[Service]
+ExecStart=/usr/bin/fluent-bit -c /etc/orca/log-shipper/fluent-bit.conf
+RuntimeDirectory=orca/alloc-log-shipper-0
+# socket: /run/orca/alloc-log-shipper-0/port-metrics.sock

examples/full-stack/rendered/systemd-web-app.service

@@ -0,0 +1,11 @@
+# Systemd unit for orca web-app service (alloc web-app-0)
+# Generated by SystemdEmitter (internal/emitter/systemd.go)
+# Path on target node: /etc/systemd/system/orca-v1-web-app.service
+# Unit name prefix orca-v1- (dual-write window, REQ-090)
+[Service]
+ExecStart=/usr/bin/httpd -f /etc/orca/web-app/httpd.conf
+ExecStartPost=/usr/local/bin/warm-cache.sh
+ExecStop=/bin/sh -c 'sleep 5'
+ExecStop=/usr/local/bin/drain.sh
+RuntimeDirectory=orca/alloc-web-app-0
+# socket: /run/orca/alloc-web-app-0/port-http.sock

examples/full-stack/rendered/traefik-dynamic-api.yaml

@@ -0,0 +1,23 @@
+# Traefik dynamic config for orca api service
+# Generated by TraefikEmitter (internal/emitter/traefik.go)
+# Path on target node: /etc/traefik/dynamic/orca-api.yaml
+# service.bind: 127.0.0.1 (TCP opt-in, R-007)
+http:
+  routers:
+    orca-api:
+      rule: PathPrefix("/api")
+      service: orca-api
+      tls:
+        certResolver: orca
+        domains:
+          - main: "cluster.orca.local"
+  services:
+    orca-api:
+      loadBalancer:
+        servers:
+          - url: "http://127.0.0.1:9090"
+          - url: "http://127.0.0.1:9090"
+        healthCheck:
+          path: /healthz
+          interval: 10s
+          timeout: 2s

examples/full-stack/rendered/traefik-dynamic-web-app.yaml

@@ -0,0 +1,24 @@
+# Traefik dynamic config for orca web-app service
+# Generated by TraefikEmitter (internal/emitter/traefik.go)
+# Path on target node: /etc/traefik/dynamic/orca-web-app.yaml
+# Atomic reload: write to .tmp + mv (gate C-10)
+http:
+  routers:
+    orca-web-app:
+      rule: PathPrefix("/web-app")
+      service: orca-web-app
+      tls:
+        certResolver: orca
+        domains:
+          - main: "cluster.orca.local"
+  services:
+    orca-web-app:
+      loadBalancer:
+        servers:
+          - url: "unix:///run/orca/alloc-web-app-0/port-http.sock"
+          - url: "unix:///run/orca/alloc-web-app-1/port-http.sock"
+          - url: "unix:///run/orca/alloc-web-app-2/port-http.sock"
+        healthCheck:
+          path: /healthz
+          interval: 5s
+          timeout: 1s