…ts to it

…ng, and per-frontend behavior

Corrects three factual errors from local review:
- $1/$2 and !`command` never existed; the resolver (pkg/runtime/commands.go)
  supports ${args[0]}, ${args.join(" ")}, ${tool_name({...})}, and the legacy
  !tool_name(...) bang syntax.
- agent: can target any agent in the team (team.Team.Agent), not just one
  listed in the current agent's sub_agents (agent_router.go, team.go,
  agent-schema.json already documented this correctly).
- url precedence over agent only holds in the full TUI (handlers.go); the
  lean TUI (leantui/update.go) only dispatches resolved text and never
  opens a browser or switches agents, and the CLI (cli/runner.go) switches
  agents but never checks url.

warn_on_cache_miss exists on main (pkg/userconfig/userconfig.go, defaults
false) and is exposed in the Notifications settings tab
(pkg/tui/dialog/settings.go) but was missing from the reference table and
complete example.

The blanket 'CLI flags override user settings' claim doesn't hold for
--yolo/--hide-tool-results: applyUserSettings (cmd/root/run.go) reapplies a
saved true setting on top of an explicit --yolo=false /
--hide-tool-results=false because those flags don't track whether they were
explicitly passed. --lean and --theme do track this and override correctly.

…ple model

URL-only commands on the CLI and lean TUI still dispatch the resolved
(usually empty) text as a user message and can trigger a model turn —
they just don't open the browser. Align with the correct wording
already used at lines 29 and 218.