Migrate a project onto a new base image without losing its volumes

Projects were pinned to the image they were first created from. Both
create paths preferred triple-c-snapshot-<id>:latest whenever it
existed, and container_needs_recreation compared the container's live
image against the triple-c.image label — which create_container wrote
from the same image it created from. A tautology that could never fire.
The only escape was Reset, which calls remove_project_volumes and
destroys the login, skills and transcripts.

Measured consequences on this host: real projects are missing socat (so
the auth bridge cannot tunnel) and bubblewrap (so sandbox mode does not
work), plus Mission Control and triple-c-sso-refresh, and sit 61
packages behind the base including ca-certificates, openssl and curl.

Detection. create_container now writes triple-c.base-image-id (the image
ID, not RepoDigests, which local-built and custom images do not have)
and triple-c.create-image. container_needs_recreation takes the expected
create-image and compares against the latter, so the check means
something. base-image-id is deliberately NOT compared: a base bump would
otherwise silently recreate from the snapshot, consuming the "you should
migrate" signal without migrating. Staleness is surfaced, never acted on
automatically.

Migration keeps the volumes. /home/claude and ~/.claude are volumes and
the image's copy is seed-only — permanently masked after first mount —
so the login, ~/.claude.json, skills, transcripts, scheduler tasks, SSH
keys, cargo, uv, ruff and Claude Code itself re-attach untouched. Only
root-level state is rebuilt: apt packages are replayed against the new
base rather than copied, so no stale libc is dragged forward, and
/usr/local, /opt and the non-bind-mounted parts of /workspace are copied
verbatim with tar --skip-old-files so they can never clobber a newer
base binary.

docker diff is not used: on a snapshot-derived container it reports only
changes since the last commit. Raw image-vs-image diffing is filtered
through dpkg ownership because it otherwise lies — 8,677 raw path
differences on a real project reduced to 2 genuinely user-authored
files, both loose /workspace-root files.

Crash safety. snapshot:latest keeps pointing at the old image until the
final commit, so any crash before it self-heals on next start. Later
crashes are caught by reconcile_project_statuses. The rollback pin is a
docker tag: 0.057s and 0 bytes. Rollback restores the system layer only
— volumes are never touched — and the UI says so rather than implying a
time machine.

Fixes an infinite recreation loop shipped with the MCP removal. docker
commit propagates labels to the image, so a container created from a
snapshot inherited its non-empty triple-c.mcp-fingerprint and the
one-shot shim recreated it again on every start, forever. Lineage labels
are now always written explicitly.

Documents the second, separate bug this uncovered: Dockerfile changes
under /home/claude never reach an existing project, migration or not,
because the volume masks them. Anything that must stay upgradable
belongs in /usr/local/bin or /opt, or must be seeded by entrypoint.sh.

145 Rust tests, 227 frontend tests, both builds clean.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

app/src/components/projects/home/OverviewTab.tsx

@@ -12,6 +12,8 @@ import PermissionModeControl, {
   permissionModePatch,
 } from "../PermissionModeControl";
 import CapabilityTiles from "./CapabilityTiles";
+import ContainerMigrationBanner from "./ContainerMigrationBanner";
+import type { ContainerMigration } from "../../../hooks/useContainerMigration";
 import SaveIndicator from "../../ui/SaveIndicator";
 import Button from "../../ui/Button";
 import { formatAge } from "./format";
@@ -31,6 +33,11 @@ interface Props {
   saveState: SaveState;
   actions: ReturnType<typeof useProjectActions>;
   onOpenTab: (tab: ProjectHomeTabId) => void;
+  /** Base-image staleness, run state and report. Owned by `ProjectHome`. */
+  migration: ContainerMigration;
+  /** Migration mirrors Reset's gate: only offered on a stopped container. */
+  canMigrate: boolean;
+  onOpenMigration: () => void;
 }
 
 export default function OverviewTab({
@@ -39,6 +46,9 @@ export default function OverviewTab({
   saveState,
   actions,
   onOpenTab,
+  migration,
+  canMigrate,
+  onOpenMigration,
 }: Props) {
   const [sessions, setSessions] = useState<ClaudeSession[]>([]);
   const [tasks, setTasks] = useState<ScheduledTask[]>([]);
@@ -120,6 +130,14 @@ export default function OverviewTab({
         </div>
       </section>
 
+      {/* A container missing socat and bwrap is a capability statement, so the
+          out-of-date warning sits directly above the capability inventory. */}
+      <ContainerMigrationBanner
+        migration={migration}
+        canMigrate={canMigrate}
+        onOpen={onOpenMigration}
+      />
+
       <CapabilityTiles
         project={project}
         onManageInTerminal={(command) => actions.openTerminalWithCommand(command)}