[claude-agent-service] Bump image_tag to 2fd7670d (45m /execute timeout)

## Context
Ships the monorepo commit
(code@2fd7670d [claude-agent-service] Raise /execute default timeout
from 15m to 45m) that raises ExecuteRequest.timeout_seconds from 900 to
2700. The auto-upgrade pipeline (DIUN → n8n → claude-agent-service →
service-upgrade agent) had been silently timing out mid-run for 3 days:
139 × 202 Accepted + 6 × TimeoutError in the last 24h, zero commits to
infra, zero Slack posts. Root cause was the 15-minute cap truncating
CAUTION-class upgrades that need to summarise multi-release changelogs,
poll Woodpecker CI, and wait on on-demand DB backup CronJobs.

## What changed
`local.image_tag` 0c24c9b6 → 2fd7670d. Image built + pushed to
registry.viktorbarzin.me/claude-agent-service:2fd7670d. Deployment is
`Recreate`, so the single pod is dropped + recreated.

## Test Plan
### Automated
`terraform plan` — `Plan: 0 to add, 1 to change, 0 to destroy` (3
container image refs flip from 0c24c9b6 → 2fd7670d).
`terraform apply` — `Apply complete! Resources: 0 added, 1 changed,
0 destroyed.`

### Manual Verification
```
$ kubectl -n claude-agent rollout status deploy/claude-agent-service --timeout=120s
deployment "claude-agent-service" successfully rolled out

$ kubectl -n claude-agent get deploy claude-agent-service \
    -o jsonpath='{.spec.template.spec.containers[0].image}'
registry.viktorbarzin.me/claude-agent-service:2fd7670d

$ kubectl -n claude-agent exec deploy/claude-agent-service -- \
    sh -c 'cd /srv && python3 -c "from app.main import ExecuteRequest; \
    print(ExecuteRequest(prompt=\"p\", agent=\"a\").timeout_seconds)"'
2700
```

Next DIUN cycle (every 6h) should land ≥1 unattended upgrade as an
infra commit + Slack message without TimeoutError in the agent logs.

Closes: code-cfy

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

stacks/claude-agent-service/main.tf

@@ -11,7 +11,7 @@ data "vault_kv_secret_v2" "viktor_secrets" {
 locals {
   namespace = "claude-agent"
   image     = "registry.viktorbarzin.me/claude-agent-service"
-  image_tag = "0c24c9b6"
+  image_tag = "2fd7670d"
   labels = {
     app = "claude-agent-service"
   }