fix(kanban): list the configured agents in the Delegate dialog (#116)

[Lexus2016]

Fixes #116.

Root cause

GET /api/external-agents answers the agent map itself (res.json(config.externalAgents || {}), server.js; the SPA reads it that way, index.html). kanban.html read res.agents off it, so since #109 the Kanban Delegate dialog showed "No agents configured (add via Settings)" on every install, including one with the four built-in agents. The missing provider, models and effort context in the report all come from that empty list: an agent card IS the provider (Codex, Gemini, Claude Code…), and Model/Effort are filled from the selected agent's catalog.

Changes (public/kanban.html)

• loadExternalAgents() reads the map; an error body or an array → {}.
• The empty state names the real place: the Agents section of the main page's sidebar, "with a command template" (terminal-only agents cannot take a delegation). The old text said "Settings", and no such place exists.
• A one-line hint under Model/Effort: the options come from the agent's own catalog, and "—" leaves the choice to the agent.
• The success toast says where to follow the run: the ⇗ badge on the card, which opens the status/dialog view.
• 5 locales; i18n-completeness 139/0.

Verification

• npm test → exit 0.
• test/kanban-delegation.test.js: new check runs the real loadExternalAgents against the server's response shape, and pins that shape in server.js. It fails against main's kanban.html.
• Headless Chromium, throwaway server, dialog opened for a real task (delegation NOT submitted, since that opens an OS terminal):
  • main: cards: [], "No agents configured (add via Settings)", even with agents configured.
  • this branch: ⚡Codex, 🟠Claude, Antigravity CLI, opencode; Model gpt-5, o4, Effort low, high from the agent's catalog; hint visible; 0 page errors.

Not in scope (answered in the issue)

• A separate Provider → Model tree: the agent card already is the provider, and models are per-agent by design (the server allow-lists them against that agent's catalog).
• A live terminal inside the board: handoff opens a terminal on the machine the studio runs on, so there is no terminal window in Docker/headless setups. Progress is visible via the ⇗ card badge → status dialog.

🤖 Generated with Claude Code