feat: permission_prompt action hints + CLI create subcommand (#5, #20)

[OneStepAt4time]

Issue #20: Permission prompt DX

When Claude Code hits a permission prompt, the API now returns actionable hints:

{
  "status": "permission_prompt",
  "details": "Claude is waiting for permission approval. POST /v1/sessions/{id}/approve to approve...",
  "actionHints": {
    "approve": { "method": "POST", "url": "/v1/sessions/{id}/approve", "description": "Approve the pending permission" },
    "reject": { "method": "POST", "url": "/v1/sessions/{id}/reject", "description": "Reject the pending permission" }
  }
}

Also available on GET /v1/sessions/:id (not just health).

Files: src/session.ts, src/server.ts, src/__tests__/permission-hints.test.ts

Issue #5 stretch: aegis-bridge create subcommand

aegis-bridge create "Build a login page" --cwd /path/to/project

• Parses brief from CLI args
• Creates session via API
• Sends brief immediately
• Prints next steps (status, read, kill URLs)
• Helpful error if server is not running

Files: src/cli.ts, src/__tests__/cli-create.test.ts

Verification

• 342 tests passing (+36 new)
• TSC: 0 errors
• aegis-bridge --help updated with create usage

Closes #5, Closes #20