Fix AP input popup flow

[AuthenticSm1les]

Fixes #145

AP mode had two issues in the access point startup flow:

• pressing n did not trigger the configured AP start path from the AP pane
• once the input flow became active, the SSID/password popup was not rendered, so the form worked but stayed invisible

This change wires the AP start/stop keybindings into the AP-mode handler and renders the AP input popup when FocusedBlock::AccessPointInput is active.

Validation:

• cargo build
• tested AP mode locally
• confirmed n shows the popup
• entered SSID/passphrase and started an AP successfully