feat: persist helm install lifecycle - #103

Summary

• detach Helm installation lifetime from the browser request while keeping Helm as the release owner
• persist owner-scoped task identity, phase, timestamps, errors, and bounded chronological logs
• recover the modal after refresh with chart, namespace, release, and task identity checks
• pause repeated polling failures and provide an explicit retry without creating a second install
• remove the abort UI because no server-side cancellation contract exists
• reject overlapping active operations for the same namespace/release and expire stale records when a replacement is requested
• keep the task read endpoint read-only so polling cannot overwrite a still-running install outcome

Follow-up sequence

#103 -> #108 -> #109

#108 and #109 remain closed until their preceding change is merged.

Owner review

1. Correct: a disconnected browser no longer owns the Helm process, and refresh recovery reads the persisted server state.
2. Complete: controller, store lifecycle, database task/log records, API polling, and frontend recovery form one data flow.
3. Focused: chart readiness and app-store defaults remain in fix: validate helm chart readiness and compatibility #108 and fix: harden app store install defaults #109.
4. Failure: stream setup failures close unstarted tasks; install and persistence failures are recorded; polling backs off and pauses; stale cleanup occurs transactionally on replacement.
5. Compatibility: stable Casdoor IDs remain unchanged, while sessions without an optional ID use a bounded deterministic Owner/Name identity.
6. Concurrency: a release-scoped active key and transaction reject overlapping installs; terminal writes are idempotent and bounded.
7. Ownership: Helm continues to own releases; this PR owns only operation lifecycle persistence and recovery.
8. Evidence: the fork experiment exercised backend, frontend, Go lint/tests, and UI tests; focused local checks cover recovery, SSE parsing, terminal persistence, and polling behavior.

Validation

• Fork experiment: https://github.com/bugkeep/casos/actions/runs/30017802242
• go test ./object ./controllers ./store
• ESLint on affected frontend files
• React test runner: 2 suites, 8 tests passed

Fix: #101