feat: support OpenHands OSS backends

[kripper]

HUMAN:
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• A human has tested these changes.

Why

To have agent+canvas + OH containers + OH self-hosted

Summay

This PR adds support for adding OpenHands OSS as an OpenHands backend in Agent Canvas.

• Add websocket_url field to AppConversation type
• Resolve relative websocketUrl against backend host, not frontend
• Add shouldUseGateway() to decide when to route through app-server proxy
• Route /btw ask_agent through OpenHands app-server proxy when gateway is available
• Allow http: protocol in device flow verification URL validation
• Force OpenHands Cloud backends to kind 'cloud' in inferKindFromHost

How to Test

• Requires: feat: OpenHands Gateway and V1 routing for self-hosted deployments + agent-canvas backend support OpenHands#14909

Type

• Bug fix
• Feature
• Refactor
• Breaking change
• Docs / chore

[vercel]

Someone is attempting to deploy a commit to the openhands Team on Vercel.

A member of the Team first needs to authorize it.

[enyst]

is this intended, isn’t “local” necessary?

[github-actions]

✅ Mock-LLM E2E Tests

60/60 passed

Commit: 15c4ab91 · Workflow run · Test artifacts

Status	Test	Duration
✅	automations/mock-llm-automation.spec.ts › mock-LLM automation lifecycle › step 1: setup LLM profile and register automation trajectory	7.2s
✅	automations/mock-llm-automation.spec.ts › mock-LLM automation lifecycle › step 2: create automation and dispatch run via the UI	28.4s
✅	automations/mock-llm-automation.spec.ts › mock-LLM automation lifecycle › step 3: verify automation and run on the automations page	6.2s
✅	automations/mock-llm-preset-automation.spec.ts › preset automation → slash command conversation › automation card sends the correct slash command to a conversation	16.0s
✅	automations/mock-llm-preset-automation.spec.ts › preset automation → slash command conversation › direct slash command from home page triggers skill activation	13.7s
✅	backends/mock-llm-auth-modes.spec.ts › auth mode: fresh install with runtime-injected key › reaches the onboarding modal without pre-seeded localStorage	1.3s
✅	backends/mock-llm-auth-modes.spec.ts › auth mode: non-public key rotation › recovers when localStorage has a stale session API key	5.3s
✅	backends/mock-llm-auth-modes.spec.ts › auth mode: public gate › shows first-run onboarding before the auth screen when no key is configured	1.4s
✅	backends/mock-llm-auth-modes.spec.ts › auth mode: public gate › rejects an incorrect key with an inline error	1.6s
✅	backends/mock-llm-auth-modes.spec.ts › auth mode: public gate › allows access after pasting the correct key	1.7s
✅	backends/mock-llm-auth-modes.spec.ts › auth mode: public gate › skips auth screen for returning user with valid stored key	747ms
✅	backends/mock-llm-auth-modes.spec.ts › auth mode: public gate › re-prompts when the server rotates its key (stale localStorage)	1.4s
✅	backends/mock-llm-cross-connect.spec.ts › cross-connect: frontend-only → backend-only › frontend-only connects to a separate backend-only instance	15.9s
✅	backends/mock-llm-cross-connect.spec.ts › cross-connect: frontend-only → multiple backends › connects to two separate backends and switches between them	20.8s
✅	backends/mock-llm-partial-stack.spec.ts › partial stack: --frontend-only › serves the frontend but returns 503 for backend routes	7.4s
✅	backends/mock-llm-partial-stack.spec.ts › partial stack: --backend-only › serves backend APIs but returns 503 for the frontend root	13.1s
✅	backends/mock-llm-partial-stack.spec.ts › partial stack: port conflict › fails with a clear error when the ingress port is occupied	103ms
✅	backends/mock-llm-partial-stack.spec.ts › partial stack: port conflict › starts successfully on a free port after a conflict	6.0s
✅	conversations/mock-llm-conversation.spec.ts › mock-LLM agent-server conversation › step 1: create an LLM profile pointing at the mock LLM server	6.2s
✅	conversations/mock-llm-conversation.spec.ts › mock-LLM agent-server conversation › step 2: activate the mock-llm profile and verify settings API	6.1s
✅	conversations/mock-llm-conversation.spec.ts › mock-LLM agent-server conversation › step 3: run a conversation with the mock LLM	6.5s
✅	conversations/mock-llm-conversation.spec.ts › mock-LLM agent-server conversation › step 4: resume conversation from sidebar after navigating away	5.7s
✅	conversations/mock-llm-image-upload.spec.ts › mock-LLM image upload › attaching an image embeds it as base64 in the LLM completion call	13.4s
✅	files/mock-llm-files-and-git.spec.ts › files tab, git control bar, and browser tab › step 1: ensure mock LLM profile is configured	7.2s
✅	files/mock-llm-files-and-git.spec.ts › files tab, git control bar, and browser tab › step 2: start conversation and attach workspace metadata	12.4s
✅	files/mock-llm-files-and-git.spec.ts › files tab, git control bar, and browser tab › step 3: git control bar shows workspace pill and git actions	25.3s
✅	files/mock-llm-files-and-git.spec.ts › files tab, git control bar, and browser tab › step 4: files tab defaults to diff view for attached workspace	5.8s
✅	files/mock-llm-files-and-git.spec.ts › files tab, git control bar, and browser tab › step 5: browser tab shows empty state	6.3s
✅	files/mock-llm-files-and-git.spec.ts › files tab, git control bar, and browser tab › step 6: files tab defaults to file-tree view without attached workspace	8.3s
✅	home/mock-llm-folder-workspace.spec.ts › mock-LLM folder browser → workspace → conversation › step 1: browse to a folder, add it as a workspace, and launch a conversation with the correct working_dir	7.7s
✅	mcp/mock-llm-mcp-github.spec.ts › MCP GitHub server install flow › step 1: GitHub card is visible on the MCP marketplace page	5.5s
✅	mcp/mock-llm-mcp-github.spec.ts › MCP GitHub server install flow › step 2: clicking GitHub card opens the install modal with correct fields	5.7s
✅	mcp/mock-llm-mcp-github.spec.ts › MCP GitHub server install flow › step 3: full install flow — fill PAT, submit, verify installed	14.5s
✅	mcp/mock-llm-mcp-github.spec.ts › MCP GitHub server install flow › step 4: installed GitHub server can be deleted	5.8s
✅	mcp/mock-llm-mcp-slack-credentials.spec.ts › MCP Test Connection credential verification (Slack) › install: invalid Slack credentials are blocked with a credential-check error	5.8s
✅	mcp/mock-llm-mcp-slack-credentials.spec.ts › MCP Test Connection credential verification (Slack) › install: a valid token missing only a scope still installs (missing_scope is not a credential failure)	5.9s
✅	mcp/mock-llm-mcp-slack-credentials.spec.ts › MCP Test Connection credential verification (Slack) › install: an older agent server that omits tool_result still installs (compat)	5.9s
✅	mcp/mock-llm-mcp-slack-credentials.spec.ts › MCP Test Connection credential verification (Slack) › edit: Test Connection verifies the stored credentials and surfaces a credential failure	5.8s
✅	mcp/mock-llm-mcp-slack-credentials.spec.ts › MCP Test Connection credential verification (Slack) › edit: Test Connection reports success for valid stored credentials	5.7s
✅	mcp/mock-llm-mcp-slack-credentials.spec.ts › MCP Test Connection credential verification (Slack) › custom (non-catalog) server: Test Connection attaches no verification probe	5.7s
✅	onboarding/mock-llm-onboarding-happy-path.spec.ts › onboarding happy path › completes the full onboarding flow and launches a conversation	4.4s
✅	onboarding/mock-llm-onboarding-regressions.spec.ts › onboarding recent regressions › keeps the modal open on backdrop click and Escape	1.3s
✅	onboarding/mock-llm-onboarding-regressions.spec.ts › onboarding recent regressions › defaults the LLM setup step to OpenAI GPT-5.5	1.5s
✅	regressions/mock-llm-ui-regressions.spec.ts › UI regressions › scopes standalone styles to the agent-server-ui shell	946ms
✅	regressions/mock-llm-ui-regressions.spec.ts › UI regressions › renders critic results on agent messages and finish actions	1.4s
✅	regressions/mock-llm-ui-regressions.spec.ts › UI regressions › loads older events when scrolling up	1.6s
✅	regressions/mock-llm-ui-regressions.spec.ts › UI regressions › selected workspace persists after navigating away and returning	2.0s
✅	regressions/mock-llm-ui-regressions.spec.ts › UI regressions › cleared sessionStorage yields empty workspace selection	947ms
✅	settings/mock-llm-acp-agent.spec.ts › mock-LLM ACP agent conversation › step 1: configure ACP agent via Settings → Agent UI	13.7s
✅	settings/mock-llm-acp-agent.spec.ts › mock-LLM ACP agent conversation › step 2: reload and verify ACP settings are persisted in UI	5.5s
✅	settings/mock-llm-acp-agent.spec.ts › mock-LLM ACP agent conversation › step 3: start ACP conversation and verify agent reply	6.7s
✅	settings/mock-llm-acp-agent.spec.ts › mock-LLM ACP agent conversation › step 4: resume ACP conversation from sidebar after navigating away	5.8s
✅	settings/mock-llm-model-switch.spec.ts › mock-LLM /model slash command › step 1: configure LLM, create switch-target profile, register trajectory	13.1s
✅	settings/mock-llm-model-switch.spec.ts › mock-LLM /model slash command › step 2: start conversation, switch profile via /model, verify switch	7.6s
✅	settings/mock-llm-profile-management.spec.ts › active profile deletion + reconciliation › active profile is deletable and reconciliation activates another profile	8.6s
✅	settings/mock-llm-profile-management.spec.ts › same-model profile identity › chat header shows the correct profile when two profiles share the same model	15.0s
✅	settings/mock-llm-profile-management.spec.ts › OpenHands provider hidden base_url preservation › re-saving an OpenHands profile from Basic view preserves hidden base_url	7.5s
✅	skills/mock-llm-skills.spec.ts › skill loading: project, user, and deletion › project skill in workspace/.agents/skills/ triggers on matching keyword	14.4s
✅	skills/mock-llm-skills.spec.ts › skill loading: project, user, and deletion › user skill in ~/.openhands/skills/ triggers on matching keyword	13.4s
✅	skills/mock-llm-skills.spec.ts › skill loading: project, user, and deletion › deleting a user skill removes it from subsequent conversations	14.3s

_{Posted by the Mock-LLM E2E workflow · results are deterministic (scripted LLM responses)}

[enyst]

@kripper Just to note, the HUMAN: note is there for the PR author to say a few sentences, in their own words, about what the PR proposes. A summary or something. We added the template and the associated CI workflow because we are drowning in AI PRs where there doesn’t seem to be a human speaking or even knowing what the PR does, so we were trying to find the signal 😅