feat: add webhookTriggerNode for receiving incoming HTTP webhooks

[DheerajShrivastav]

Closes #12

What

Implements webhookTriggerNode — a configuration and validation node that processes
incoming HTTP webhook payloads. The node does not spin up an HTTP server. Instead, the
host application registers the route and injects the incoming request into
context.variables.webhookRequest before calling the executor.

Changes

• packages/nodes/src/logic/webhook-trigger.ts — full node implementation
• packages/nodes/src/logic/__tests__/webhook-trigger.test.ts — 31 tests across 8 suites
• packages/nodes/src/logic/index.ts — exports node, schemas, and types
• packages/nodes/src/index.ts — registers node in named exports and builtInNodes

Behaviour

The executor:

1. Reads webhookRequest from context.variables
2. Validates the HTTP method matches the configured method
3. Runs the configured auth check
4. Returns the processed payload as structured output

Auth types supported:

Type	How it works
none	No check, always passes
basic	Decodes Authorization: Basic <base64>, compares username + password
header	Checks each configured key/value pair against incoming headers (case-insensitive)

Output fields: body, headers, method, path, query, timestamp,
authenticated, responseCode, responseData

The executor surfaces responseCode (defaults to 200) and responseData directly
in the result so the host app can send the configured HTTP response without needing
to hold onto the input config separately.

Acceptance criteria

• HTTP endpoint creation — path + method in input schema for host app route registration
• Multiple auth methods — none, basic, header
• Custom response configuration — responseCode and responseData in both input
  schema and executor output
• Zod schemas for input/output — WebhookTriggerInputSchema, WebhookTriggerOutputSchema
• Unit tests

Testing

pnpm build                          # passes
pnpm --filter @jam-nodes/nodes test # 128 tests total, 31 new — 0 failures
npx tsx test-webhook.ts             # 11 manual tests — 0 failures