polish: Operations + Shared Context UX overhaul

feat: Fellowship Operations + Shared Context pages

feat: editable agent config + cron management UI

feat: enhanced Session Waterfall View (CC-P1)

feat: enhanced Cost Analytics Dashboard (CC-P1)

feat: enhanced Token Usage Charts (CC-P1)

fix: resolve all 4 security issues (#4, #5, #6, #7)

feat(fleet): add fleet comparison matrix page

feat(agent-detail): add memory timeline and health sparklines

feat(dashboard): add skills count to agent cards

feat: compact view, security hardening, skills/credentials panels, cooldown reset

feat: add calendar view for cron jobs

fix: use full path for clawdbot binary in crons endpoint

fix: crons endpoint use CLI instead of gateway HTTP proxy

fix: crons endpoint - remove stale await import, fix homedir