Add call graph fixtures for various languages and scenarios

- Introduced `all-edge-reasons.json` to test edge resolution reasons in .NET.
- Added `all-visibility-levels.json` to validate method visibility levels in .NET.
- Created `dotnet-aspnetcore-minimal.json` for a minimal ASP.NET Core application.
- Included `go-gin-api.json` for a Go Gin API application structure.
- Added `java-spring-boot.json` for the Spring PetClinic application in Java.
- Introduced `legacy-no-schema.json` for legacy application structure without schema.
- Created `node-express-api.json` for an Express.js API application structure.

docs/modules/cli/guides/airgap.md

@@ -2,6 +2,20 @@
 
 Offline/air-gapped usage patterns for the Stella CLI.
 
+## Offline kit commands
+- Import an offline kit (local verification + activation)
+  ```bash
+  stella offline import \
+    --bundle ./bundle-2025-12-14.tar.zst \
+    --verify-dsse \
+    --verify-rekor \
+    --trust-root /evidence/keys/roots/stella-root.pub
+  ```
+- Check current offline kit status
+  ```bash
+  stella offline status --output table
+  ```
+
 ## Prerequisites
 - CLI installed from offline bundle; `local-nugets/` and cached plugins available.
 - Mirror/Bootstrap bundles staged locally; no external network required.

docs/modules/cli/guides/commands/offline.md

@@ -0,0 +1,44 @@
+# stella offline — Command Guide
+
+## Overview
+
+The `stella offline` command group manages air-gap “offline kits” locally, with verification (DSSE + optional Rekor receipt checks), monotonic version gating, and quarantine on validation failures.
+
+## Commands
+
+### `offline import`
+
+```bash
+stella offline import \
+  --bundle ./bundle-2025-12-14.tar.zst \
+  --verify-dsse \
+  --verify-rekor \
+  --trust-root /evidence/keys/roots/stella-root.pub
+```
+
+**Notes**
+- `--verify-dsse` defaults to `true` and requires `--trust-root`.
+- `--force-activate` requires `--force-reason` and records a non-monotonic activation override.
+- `--dry-run` validates the kit without activating it.
+- Uses the configured kits directory (default `offline-kits/`) for state (`offline-kits/.state/`) and quarantine (`offline-kits/quarantine/`).
+
+### `offline status`
+
+```bash
+stella offline status --output json
+```
+
+Displays the currently active kit (if any), staleness, and quarantined bundle count.
+
+## Exit codes
+
+Offline exit codes are defined in `src/Cli/StellaOps.Cli/Commands/OfflineExitCodes.cs` (advisory A11), including:
+- `0` success
+- `1` file not found
+- `2` checksum mismatch
+- `5` DSSE verification failed
+- `6` Rekor verification failed
+- `8` version non-monotonic (not force-activated)
+- `11` validation failed
+- `130` cancelled
+