feat(ask): add list endpoint for questions

[geoffjay]

Context

Part of #869 (ask service epic).

The ask service has endpoints to trigger checks and answer questions, but no way to list or query existing questions. Users and agents cannot discover what questions are pending without already knowing the question UUID.

Problem

• No API endpoint to list questions (pending, answered, all)
• No CLI command to view pending questions
• Agents can't discover questions programmatically
• The get_active_questions() method exists in AppState but is unused (#[allow(dead_code)])

Acceptance Criteria

API

• Add GET /questions endpoint that returns a list of questions
• Support query parameters for filtering:
  • status (optional): pending, answered, expired, or omit for all
  • limit (optional, default 50): maximum number of results
  • offset (optional, default 0): pagination offset
• Add GET /questions/:id endpoint to get a single question by UUID
• Return questions sorted by asked_at descending (newest first)

Client

• Add list_questions() method to AskClient in crates/ask/src/client.rs
• Add get_question() method to AskClient

CLI

• Add agentd ask list subcommand with --status filter flag
• Add agentd ask get <question-id> subcommand
• Formatted table output for list, detailed output for get
• Support --json flag for raw output

Skill

• Update .claude/skills/agent-ask/SKILL.md to document the new commands

Relevant Files

• crates/ask/src/api.rs -- add new route handlers
• crates/ask/src/state.rs -- get_active_questions() already exists, add list_all()
• crates/ask/src/client.rs -- add client methods
• crates/ask/src/types.rs -- add ListQuestionsRequest/ListQuestionsResponse types
• crates/cli/src/commands/ask.rs -- add List and Get CLI subcommands
• .claude/skills/agent-ask/SKILL.md -- update docs

Blocked By

• feat(ask): add SQLite persistence with SeaORM #870 (SQLite persistence) -- list endpoint should query the database, not just in-memory state

Stack Base

Branch off feature/autonomous-pipeline and PR back into it.