feat(ops): self-heal disk pressure instead of only alerting

The 5-minute disk probe now reclaims storage automatically: from 85% it runs the gentle age-windowed Docker prune, from 90% it drops the age windows (docker-prune.sh --force: all unused build cache and unreferenced images, all stopped containers) so a mount can never silently max out. Alerts still fire at 85/90/95% and their hint now points at non-Docker growth when reclaiming is not enough. Force mode is reserved for the worker; deploys keep the gentle mode. Volumes are off-limits in every path.

src/lib/deploy-workflow-contract.test.ts

@@ -36,6 +36,12 @@ it("preserves production runtime configuration and recent cache", () => {
 	);
 	expect(prune).toContain('docker image prune -af --filter "until=168h"');
 	expect(prune).toContain('docker container prune -f --filter "until=24h"');
+	// Emergency `--force` mode drops every age window to reclaim unused bytes,
+	// but even then volumes are off-limits.
+	expect(prune).toContain('== "--force" ]]');
+	expect(prune).toContain("FORCE=1");
+	expect(prune).toContain("(( FORCE ))");
+	expect(deploy).not.toContain("--force");
 	expect(deploy).not.toContain("docker volume prune");
 	expect(prune).not.toContain("docker volume prune");
 });