New "Egress" tab on agent detail showing:
- Active integration presets (colored pills)
- Allowed/blocked domains
- Per-tool restrictions table (tool -> allowed domains)
- Available presets list with descriptions
- Instructions for YAML config

Also: fix em dash in OpenClaw product description

Security Posture:
- Severity badges are now filled pills (background + text color)
  matching the dashboard design system, not just text with border

Agent detail:
- New "Sessions" section in Overview tab showing recent sessions
  for this agent with events, duration, threats, and risk score
- Links to session trace page

Egress tab:
- Shows integration presets, allowed/blocked domains, tool restrictions
- Available presets list with descriptions

Full CRUD for egress policies from the dashboard:
- Integration presets as checkboxes (16 services)
- Allowed/blocked domains as text inputs
- Per-tool restrictions with add/remove
- Saves to config on submit, persists to oktsec.yaml
- POST /dashboard/agents/{name}/egress endpoint
- listContains template function for checkbox state

Hero stat cells use flexbox column with justify-content:center
so all 4 cells align vertically regardless of content height
(the posture score ring is taller than plain numbers).

Move Sessions table out of the comm partners grid row into a new
ad-grid alongside Recent Messages so they display as 2 columns.

Row 1: Sessions + Recent Messages (2 columns)
Row 2: Top Triggered Rules + Communication Partners (2 columns)
Row 3: LLM Threat Intelligence (full width, if data exists)

Agents page uses 2-column layout when discovered agents exist:
left column is the registered agents grid, right column (280px)
is the discovered from traffic sidebar with register buttons.