perf(rpc): performance + async lifecycle closure

[beruro]

Summary

Performance / lifecycle closure for the RPC + async layers (8 commits):

• perf(diagnostics): bound RPC latency aggregation
• perf(streaming): coalesce state IPC edges
• perf(cli): replace reconciliation polling with intent push
• refactor(async): add scoped resource lifecycle
• refactor(data): scope shared application loaders
• refactor(projects): fence scoped loader results
• perf(polling): suspend hidden resource refreshes
• docs(audit): record async lifecycle verdicts

Notes

• Branch predates latest develop; rebase/update before merge.
• First of a batched split of a large local working tree.

Test plan

• cargo check / clippy (backend)
• pnpm typecheck + vitest (frontend)
• Manual: hidden-tab refresh suspension; CLI intent-push path