Migrate selected templates from langgraph dev to agentseek-api

[kic635]

Migrate migrated templates from langgraph dev to agentseek-api

Background

Some AgentSeek templates currently use langgraph dev as their backend
runtime. That command is useful for LangGraph graph prototyping, but it does
not exercise the AgentSeek API runtime that generated projects are expected to
use.

This issue tracks the template-side migration:

template backend: langgraph dev → agentseek-api dev

agentseek remains responsible for project creation and lifecycle management.
agentseek-api is the runtime dependency owned by the generated project.

Goal

For templates explicitly migrated in this issue, the normal flow remains:

agentseek create <template>
cd <generated-project>
agentseek task sync
agentseek dev

The generated backend should start with agentseek-api dev on the template's
declared port, while preserving the existing graph entrypoints and frontend
protocol.

Required changes

• Replace the default backend command with agentseek-api dev for the selected
  migrated templates.
• Add the agentseek-api dependency to those generated projects.
• Keep existing langgraph.json and graph references working unless a
  template-specific incompatibility is documented.
• Keep lifecycle metadata, health checks, README instructions, and generated
  .env.example consistent with the new command.
• For templates covered by this issue, agentseek-api dev is the only
  supported backend runtime. Templates that have not been migrated are outside
  this issue's scope.

Acceptance criteria for each migrated template

• The generated project contains the expected agentseek-api dependency.
• agentseek dev --dry-run shows the AgentSeek API backend command and the
  declared backend URL/health check.
• agentseek dev starts the backend through agentseek-api dev.
• The existing langgraph.json and graph reference load successfully.
• The backend health endpoint responds successfully.
• The registered graph is discoverable through the compatible
  /assistants endpoint.
• The existing frontend can create a thread and consume one streaming run
  without a frontend rewrite.
• agentseek info, agentseek doctor, and agentseek doctor --live
  describe the generated project's backend correctly.
• Template rendering, dependency installation, and documented startup
  steps pass in CI.

Persistence boundary

Checkpoint and thread persistence is not a universal requirement for every
template. It is required only for templates that explicitly opt into a
persistent AgentSeek API store (for example, embedded SeekDB) and must be
covered by a separate template/API integration test. Templates using an
in-memory checkpointer must document that restart persistence is not provided.

The AgentSeek API repository owns the generic persistence, authentication,
CORS, Studio, OpenAPI, and protocol compatibility guarantees. This issue only
verifies those surfaces for a migrated template when the template actually
uses them.

Out of scope

• Rewriting the AgentSeek lifecycle system.
• Rewriting template frontends.
• Replacing agentseek with agentseek-api.
• Making SeekDB, distributed workers, Studio, MCP, or A2A mandatory for every
  template.
• Changing templates that intentionally retain Bub or another explicit
  runtime.

Test strategy

The migration should include:

1. AgentSeek lifecycle CLI tests for info, doctor, doctor --live, and
   dev --dry-run.
2. Template render/dependency smoke tests for each migrated template.
3. A live API smoke test for at least one representative migrated template:
   health → assistant discovery → thread creation → streaming run.
4. A restart/persistence test only for templates configured with a persistent
   SeekDB checkpointer.

For templates covered by this issue, agentseek-api dev is the only supported
backend runtime.