### What problem does this PR solve?
Add two API in go
```
/api/v1/agents/test_db_connection POST
/api/v1/agents/<agent_id>/sessions DELETE
```
### Type of change
- [x] New Feature (non-breaking change which adds functionality)
---------
Co-authored-by: Yingfeng <yingfeng.zhang@gmail.com>
### Description
This PR ports the `GET /api/v1/agents/prompts` endpoint from the Python
backend to the Go backend.
### Changes Made
- **Handler**: Added `GetPrompts` method to `internal/handler/agent.go`.
- **Router**: Registered the `agents.GET("/prompts")` route in
`internal/router/router.go`.
- **Logic**: Leveraged the existing `service.LoadPrompt` utility to read
`analyze_task_system`, `analyze_task_user`, `next_step`, `reflect`, and
`citation_prompt` templates directly from the `rag/prompts` directory.
- **Unit Test**: Added `TestGetPrompts_Success` to
`internal/handler/agent_test.go` to mock the HTTP context and validate
the JSON response structure.
### Motivation
This is part of the ongoing effort to port the Agent API surface to Go.
Since this specific endpoint only serves static prompt templates and
does not require the complex DAG/Canvas execution engine, it can be
seamlessly and safely handled by the Go backend.
### Testing
- [x] Added automated unit test `TestGetPrompts_Success` (verified
passing).
- [x] Tested locally via `curl` against the Go server (port 9380) and
Python server (port 9384).
- [x] Verified that the Go JSON response structure and loaded prompt
text are logically 100% identical to the Python implementation.
### What problem does this PR solve?
As Title
Codes were tested by Postman
### Type of change
- [x] New Feature (non-breaking change which adds functionality)
## Summary
Port the canvas-template catalogue endpoint to the Go API server. Listed
in the Go-API port checklist of #15240.
Mirrors `list_agent_template` in `api/apps/restful_apis/agent_api.py`:
returns every row from the `canvas_template` table so that the UI can
render the template gallery on the New-Agent screen.
## What
- `internal/dao/canvas_template.go` — new `CanvasTemplateDAO.GetAll()`
ordered by `create_time desc` (newest templates first).
- `internal/service/agent.go` — wire the new DAO into `AgentService` and
expose `ListTemplates() ([]*entity.CanvasTemplate, error)`.
- `internal/handler/agent.go` — new `AgentHandler.ListTemplates` HTTP
handler (auth-gated, mirrors Python `@login_required`).
- `internal/router/router.go` — `agents.GET("/templates",
r.agentHandler.ListTemplates)` registered alongside the existing `GET
/agents`.
- `internal/handler/agent_test.go` — three new tests covering: success
path, empty-list → JSON array (not `null`), and the auth gate.
## Notes
- `CanvasTemplate` entity, GORM tags, and DB migration already exist in
`internal/entity/canvas.go` and `internal/dao/database.go` — no schema
change required.
- The handler coerces a `nil` slice to `[]*entity.CanvasTemplate{}` so
the JSON payload is always an array (the frontend does `data.map(...)`
on it).
## Test plan
- [x] `go vet ./internal/handler ./internal/service ./internal/dao
./internal/router` clean
- [x] Three unit tests added; existing `TestListAgents_Success`
untouched
- [ ] CI runs `go test ./internal/handler` with cgo binding linked
## Related
- Tracker: #15240
## Summary
Implement the `GET /api/v1/agents/<agent_id>/versions/<version_id>`
endpoint in Go, returning full version details including DSL.
Depends on #15629 which introduced the version list endpoint and
`UserCanvasVersionDAO` infrastructure.
### Changes
- **Modified**: `internal/handler/agent.go` — Added `GetAgentVersion`
handler with auth check and ownership verification
- **Modified**: `internal/router/router.go` — Registered `GET
/:agent_id/versions/:version_id` route
- **New/Modified tests**: Service and handler tests for the version
detail endpoint
### Testing
```
=== RUN TestGetVersion_Success --- PASS
=== RUN TestGetVersion_WrongCanvas --- PASS
=== RUN TestGetVersion_NotFound --- PASS
=== RUN TestGetAgentVersionHandler_Success --- PASS
=== RUN TestGetAgentVersionHandler_VersionNotFound --- PASS
```
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
---------
Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>
## Summary
Closes: #15328
- Implements `GET /api/v1/agents` — the agent/canvas listing endpoint
needed to complete the Home dashboard tile in `web/src/pages/home/`.
- Mirrors Python `api/apps/restful_apis/agent_api.py::list_agents`
exactly: tenant-join auth, optional `owner_ids` guard, keyword filter,
pagination, ordering, and `canvas_category` filter (default:
`agent_canvas`).
- **Scope:** read-only list only. Full agent CRUD and canvas runtime are
explicitly out of scope (separate slice of #15240).
