fix(deploy): Checkpoints — preserve STOPPED history, fix filter + placement

- Backend: rename deleteTerminalByAppAndEnvironment → deleteFailedByAppAndEnvironment.
  STOPPED rows were being wiped on every redeploy, so Checkpoints was always empty.
  Now only FAILED rows are pruned; STOPPED deployments are retained as restorable
  checkpoints (they still carry deployed_config_snapshot from their RUNNING window).
- UI filter: any deployment with a snapshot is a checkpoint (was RUNNING|DEGRADED only,
  which excluded the main case — the previous blue/green deployment now in STOPPED).
- UI placement: Checkpoints disclosure now renders inside IdentitySection, matching
  the design spec.

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

.claude/rules/core-classes.md

@@ -32,7 +32,7 @@ paths:
 - `DeploymentStatus` — enum: STOPPED, STARTING, RUNNING, DEGRADED, STOPPING, FAILED. `DEGRADED` is reserved for post-deploy drift (a replica died after RUNNING); `DeploymentExecutor` now marks partial-healthy deploys FAILED, not DEGRADED.
 - `DeployStage` — enum: PRE_FLIGHT, PULL_IMAGE, CREATE_NETWORK, START_REPLICAS, HEALTH_CHECK, SWAP_TRAFFIC, COMPLETE
 - `DeploymentStrategy` — enum: BLUE_GREEN, ROLLING. Stored on `ResolvedContainerConfig.deploymentStrategy` as kebab-case string (`"blue-green"` / `"rolling"`). `fromWire(String)` is the only conversion entry point; unknown/null inputs fall back to BLUE_GREEN so the executor dispatch site never null-checks or throws.
-- `DeploymentService` — createDeployment (deletes terminal deployments first), markRunning, markFailed, markStopped
+- `DeploymentService` — createDeployment (calls `deleteFailedByAppAndEnvironment` first so FAILED rows don't pile up; STOPPED rows are preserved as restorable checkpoints), markRunning, markFailed, markStopped
 - `RuntimeType` — enum: AUTO, SPRING_BOOT, QUARKUS, PLAIN_JAVA, NATIVE
 - `RuntimeDetector` — probes JAR files at upload time: detects runtime from manifest Main-Class (Spring Boot loader, Quarkus entry point, plain Java) or native binary (non-ZIP magic bytes)
 - `ContainerRequest` — record: 20 fields for Docker container creation (includes runtimeType, customArgs, mainClass)

.claude/rules/docker-orchestration.md

@@ -49,7 +49,7 @@ Traffic routing is implicit: Traefik labels (`cameleer.app`, `cameleer.environme
 
 **Deploy stages** (`DeployStage`): PRE_FLIGHT -> PULL_IMAGE -> CREATE_NETWORK -> START_REPLICAS -> HEALTH_CHECK -> SWAP_TRAFFIC -> COMPLETE (or FAILED at any stage). Rolling reuses the same stage labels inside the per-replica loop; the UI progress bar shows the most recent stage.
 
-**Deployment uniqueness**: `DeploymentService.createDeployment()` deletes any STOPPED/FAILED deployments for the same app+environment before creating a new one, preventing duplicate rows.
+**Deployment retention**: `DeploymentService.createDeployment()` deletes FAILED deployments for the same app+environment before creating a new one, preventing failed-attempt buildup. STOPPED deployments are preserved as restorable checkpoints — the UI Checkpoints disclosure lists every deployment with a non-null `deployed_config_snapshot` (RUNNING, DEGRADED, STOPPED) minus the current one.
 
 ## JAR Management