ref(pipeline): Remove now unused legacy integrationPipeline views

[evanpurkhiser]

Removes all the supporting code for the "old-style" pipleine views that
were rendered via a django template that rendered react (outside of the
usual way the app boots)

Should only be deployed once GitHub and AWS Lambda Integrations are 100%
API driven.

Refs VDY-80: Remove legacy AWS Lambda integration setup views
Refs VDY-55: Remove legacy GitHub integration setup views

[linear-code]

VDY-80 Remove legacy AWS Lambda integration setup views

VDY-55 Remove legacy GitHub integration setup views

[sentry]

Bug: The pipeline webpack entrypoint is removed, but the react_pipeline.html template still references the deleted entrypoints/pipeline.js asset, which will cause a KeyError in legacy integration views.
_{Severity: HIGH}

Suggested Fix

Remove the legacy pipeline views and the react_pipeline.html template that depends on the deleted asset. Alternatively, restore the pipeline entrypoint in rspack.config.ts until all dependent integrations are fully migrated to the new API-driven approach and the old views are confirmed to be unused.

Prompt for AI Agent

Review the code at the location below. A potential bug has been identified by an AI
agent. Verify if this is a real issue. If it is, propose a fix; if not, explain why it's
not valid.

Location: rspack.config.ts#L255-L260

Potential issue: The removal of the `pipeline` webpack entrypoint in `rspack.config.ts`
prevents the `entrypoints/pipeline.js` bundle from being generated. However, legacy
pipeline views for AWS Lambda and GitHub integrations still render the
`react_pipeline.html` template, which attempts to load this deleted asset. In production
deployments that use a `frontend-versions.json` manifest, the asset lookup function
`get_frontend_app_asset_url` will fail to find the `pipeline.js` key. This will raise a
`KeyError` and cause a runtime crash for users in these legacy integration setup flows.

Also affects:

• src/sentry/templates/sentry/bases/react_pipeline.html:17
• src/sentry/integrations/aws_lambda/integration.py
• src/sentry/integrations/github/integration.py

_{Did we get this right? 👍 / 👎 to inform future reviews.}

[cursor]

Cursor Bugbot has reviewed your changes and found 1 potential issue.

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^{Reviewed by Cursor Bugbot for commit 2925897. Configure here.}

[sentry]

Bug: The pipeline webpack entrypoint is removed, but the react_pipeline.html template still references it. This will cause a KeyError when rendering legacy integration setup views.
_{Severity: CRITICAL}

Suggested Fix

Remove the react_pipeline.html template and all backend code paths in the AWS Lambda and GitHub integrations that call render_react_view() to render it. This ensures the legacy, now-broken, frontend pipeline views are fully decommissioned and cannot be accessed.

Prompt for AI Agent

Review the code at the location below. A potential bug has been identified by an AI
agent. Verify if this is a real issue. If it is, propose a fix; if not, explain why it's
not valid.

Location: rspack.config.ts#L255-L260

Potential issue: The PR removes the `pipeline` webpack entrypoint from
`rspack.config.ts`. However, the backend template
`src/sentry/templates/sentry/bases/react_pipeline.html` still attempts to load the
corresponding asset (`entrypoints/pipeline.js`). In production, this will cause a
`KeyError` when the asset is not found in the manifest file. This template is rendered
by legacy integration pipeline views for AWS Lambda and GitHub. While the intention is
for these integrations to be fully API-driven, if any code path still triggers the old
views (e.g., due to incomplete rollout or misconfiguration), it will result in a server
error, breaking the integration setup flow for users.

Also affects:

• src/sentry/integrations/aws_lambda/integration.py
• src/sentry/integrations/github/integration.py
• src/sentry/templates/sentry/bases/react_pipeline.html:17