Refactor: Align CUE compatibility caching with pkg/cache

[roguepikachu]

Is your feature request related to a problem? Please describe.
CUE compatibility caching already lives under github.com/kubevela/pkg/cue/upgrade and is consumed by this repo through the pkg dependency. As github.com/kubevela/pkg/cache becomes the shared cache surface, CUE compat caching should align with that package (in pkg) and workflow should pick up the dependency bump so there is one cache story across repos.

Describe the solution you'd like
Scope for this workflow issue:

1. Coordinate / land the pkg-side alignment of cue/upgrade caching with pkg/cache (kubevela/pkg), if not already done there.
2. Bump github.com/kubevela/pkg in this repo and fix any call-site fallout.
3. Do not add a parallel CUE-compat cache implementation inside workflow.

Keep CUE upgrade behavior equivalent; this is an alignment / dependency update, not a new feature.

Describe alternatives you've considered

• Reimplement CUE compat caching inside workflow on pkg/cache. Rejected: ownership belongs in pkg; duplication would drift.
• Leave cue/upgrade's private cache forever. Rejected long-term if the project standardizes on pkg/cache.

Additional context

• Primary code ownership: kubevela/pkg/cue/upgrade.
• Related: Replace StepStatusCache sync.Map with Cache from kubevela/pkg #239 / Refactor: Use generalized cache for StepStatusCache. #240, Refactor: Use generalized LRU cache for HTTP provider rate limiter #247 / Refactor: Use generalized LRU cache for rate limiter cache. #249, Introduce cache package pkg#130 / Chore(deps): bump github.com/containerd/containerd from 1.6.12 to 1.6.18 #136 / Chore: refactor suspend step and add op.#Suspend #138.
• Sibling migrations in this repo: email sync.Map, optional in-memory context storage, workflow memory context store.
• Good first issue for the workflow half once the pkg change exists: mostly a module bump and smoke/tests. Prefer pairing with a pkg issue if the pkg-side work is still open.