feat: expose operation graph in progress report

[dmmordvi]

Summary

The legacy progress report now exposes the plan as a graph: every operation carries id, category and dependsOn, meta and release operations are included, and all plans of a run are reported as one flat, topologically ordered slice. stageReports and waitingFor are removed. docs/progress-report.md describes the report for library consumers.

Key changes

• progrep.Operation gains id, category, dependsOn; StageReport and waitingFor are gone, ProgressReport is a single operations slice.
• Meta (StageStart/StageEnd) and release (CreateRelease/UpdateRelease/DeleteRelease) operations are reported, so cross-stage dependencies are visible.
• Plans of a run are chained: later plans get an ordinal id prefix, their roots depend on the previous plan's sinks, and never-started operations of a finished plan become Canceled (new status), so the final snapshot has no Pending.
• Untouched resources are those without plan operations, reported for the first plan only; NoUntouchedResources is removed, UntouchedResourcesOnly covers skipped plans.
• ReleaseInstall and ReleaseUninstall close LegacyProgressReportCh on every return path, including early errors, so a consumer can range over it.
• AutoRollback together with LegacyProgressReportCh is rejected; the unreachable rollback reporter plumbing is removed.

Why

The consumer received a flat list with no structure: meta and release operations were filtered out, so waitingFor only worked within a single chain and dependencies between resources in different stages were invisible. The graph lets the consumer render progress and ordering without reconstructing the plan.

Verification

• task test:unit paths="./pkg/plan ./pkg/action" tags=ai_tests, including a test that builds a real install plan and failure plan via BuildPlan/BuildFailurePlan and checks the reported graph end to end.
• Manual runs against minikube with a successful chart, a chart skipped as up to date, and two failing charts (with and without resource operations in the failure plan); the reports match the documented shape, Canceled and the 2/ prefix included.

Review focus / risks

• Breaking JSON shape for the consumer: stageReports and waitingFor disappear, meta and release operations appear in the list, so progress counters must filter by category; must be rolled out together with the consumer side.
• NoOp/Completed for untouched resources now also covers resources absent from the cluster whose creation a policy skipped; it means "nothing was done", not "resource exists".
• Rejecting AutoRollback with LegacyProgressReportCh is a user-facing restriction; rollback reporting needs its own design.
• Closing the channel on every path changes when a consumer sees the close after a Timeout: at return, while the deployment may still be winding down inside nelm.