sub menu search - workload view

[dgunzy]

Workload drill-down + submenu filtering

Closes #194, closes #128

Workload drill-down (#194)

The graph no longer ends at the Flux resource boundary. Enter on a graph
workload group opens the workload list; from there:

• Enter opens a workload's detail — rollout status and replica health
  (Deployment/StatefulSet/DaemonSet/CronJob aware), containers with images,
  a pods table (phase, ready, restarts, age), and the workload's events
• l streams a pod's logs (directly for a single pod, via a pod picker
  otherwise) — works from both the list and the detail, and Back returns to
  wherever l was pressed
• Esc walks the whole chain in reverse: logs → detail → list → graph

Read-only v1. Verified live: a new regression test fetches the real
source-controller Deployment on the dev cluster (pods, containers, events).

Submenu filtering + paging (#128)

Submenus (:ctx, :skin, :logs, pod picker) now filter with the same
keys as the resource list: / to filter (cursor shown in the title),
type to narrow, Enter to apply, Esc to cancel. PageUp/PageDown (or
Ctrl+f/b) page through long menus, and : drops straight into command
mode.

Fixed

• Submenu selections no longer scroll below the visible popup — the scroll is
  reconciled at render time with the popup's actual height instead of a
  hardcoded 20-row estimate in the key handler (regression-tested at multiple
  heights)
• Submenus and the quit dialog no longer hardcode black backgrounds or
  low-contrast title colors; they follow the active skin like every other
  overlay (full-codebase hardcoded-color sweep is clean)

Testing

661 unit/integration tests passing (just ci green), including the full
filter-mode lifecycle, the drill-down navigation chain, and the logs
back-target from both entry points. 6/6 live tests green against the dev
kind clusters (just test-live).