feat: webhook system with retain.completed event, UI, and docs (#487)

* doc: update cookbook

* fix(cookbook): preserve tag keys during sync, strip local .md links

- Fix extract_tags_from_readme/notebook to return dict[str,str] preserving
  sdk/topic keys instead of bare values, preventing topics like
  "Customer Service" from being misclassified as SDK
- Add strip_local_md_links() to remove relative .md references that
  would cause broken link errors in Docusaurus build

* ci: run test-doc-examples independently without waiting for test-rust-cli

Build the CLI directly in the job instead of downloading the artifact,
so test-doc-examples can start at the beginning in parallel with all other jobs.

* feat: webhook system with task-owned retry, retain.completed event, and UI

- New webhook system: register per-bank webhooks with HMAC signing, configurable
  HTTP method/timeout/headers/params (http_config JSONB), and PATCH support
- Webhook deliveries run as async_operations (webhook_delivery type) with
  task-owned retry via RetryTaskAt exception and exponential backoff
  (60s / 5m / 30m / 2h / 8h, max 6 attempts)
- New retain.completed event fires per-document for both sync and async retain
- Delivery debug info (status code, response body) stored in result_metadata
- Control plane UI: webhooks tab per bank with create/edit/delete and a
  deliveries table with cursor pagination and expandable response details
- 28 webhook tests covering HMAC signing, delivery retries, CRUD endpoints,
  PATCH update, and retain.completed queuing
- Docs page at developer/api/webhooks documenting event payloads and delivery
- OpenAPI spec and all client SDKs (Python, TypeScript, Rust, Go) regenerated

* fix: update tests for task-owned retry model and guard _webhook_manager attribute

- test_worker.py: test_executor_exception_triggers_retry now raises RetryTaskAt
  (plain exceptions are immediate failures in the new system); rename
  test_executor_exception_marks_failed_after_max_retries to
  test_executor_exception_marks_failed_immediately to reflect new semantics
- test_batch_api.py: remove max_retries kwarg from WorkerPoller constructor
- memory_engine.py: use getattr for _webhook_manager in _fire_retain_webhook
  to avoid AttributeError when engine is created without __init__ (tests)

* fix: remove max_retries from benchmark WorkerPoller call

* fix(webhooks): transactional outbox, observations_deleted tracking, sidebar

- Queue webhook delivery rows atomically with the primary operation using the
  transactional outbox pattern — prevents lost events on process crash:
  - Retain (sync + async): outbox_callback passed into orchestrator.retain_batch
    and called inside the DB transaction, replacing the post-commit fire call
  - Consolidation: new _mark_operation_completed_and_fire_webhook combines the
    status UPDATE and webhook INSERT in one transaction
  - Added fire_event_with_conn() to WebhookManager for in-connection delivery

- Track observations_deleted count in consolidation stats and expose it in the
  consolidation.completed webhook payload (was always None)

- Add Webhooks page to docs sidebar

- Document at-least-once delivery guarantee with operation_id dedup guidance

* fix(ui): add retain.completed to available webhook event types

* feat(ui): add delete confirmation dialog for webhooks

* fix(webhooks): include operation_id in task_payload so delivery is marked completed

The task_payload JSON was missing the operation_id field, causing execute_task
to see operation_id=None and skip _mark_operation_completed — leaving every
delivery row stuck in 'pending' forever.

Added a test that inserts a real async_operations row and verifies the status
transitions to 'completed' after a successful execute_task call.

* style: fix prettier formatting in webhooks-view

Author: nicoloboschi

hindsight-api/hindsight_api/alembic/versions/e4f5a6b7c8d9_add_webhooks_tables.py

@@ -0,0 +1,62 @@
+"""Add webhooks table and next_retry_at to async_operations.
+
+Webhook deliveries are handled as async_operations tasks (operation_type='webhook_delivery')
+rather than a dedicated webhook_deliveries table.
+
+Revision ID: e4f5a6b7c8d9
+Revises: d2e3f4a5b6c7
+Create Date: 2026-03-04
+"""
+
+from collections.abc import Sequence
+
+from alembic import context, op
+
+revision: str = "e4f5a6b7c8d9"
+down_revision: str | Sequence[str] | None = "d2e3f4a5b6c7"
+branch_labels: str | Sequence[str] | None = None
+depends_on: str | Sequence[str] | None = None
+
+
+def _get_schema_prefix() -> str:
+    schema = context.config.get_main_option("target_schema")
+    return f'"{schema}".' if schema else ""
+
+
+def upgrade() -> None:
+    schema = _get_schema_prefix()
+
+    op.execute(
+        f"""
+        CREATE TABLE IF NOT EXISTS {schema}webhooks (
+            id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+            bank_id TEXT,
+            url TEXT NOT NULL,
+            secret TEXT,
+            event_types TEXT[] NOT NULL DEFAULT '{{}}',
+            enabled BOOLEAN NOT NULL DEFAULT TRUE,
+            created_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+            updated_at TIMESTAMPTZ NOT NULL DEFAULT NOW()
+        )
+        """
+    )
+
+    # Index for bank-scoped webhook lookup
+    op.execute(f"CREATE INDEX IF NOT EXISTS idx_webhooks_bank_id ON {schema}webhooks(bank_id)")
+
+    # Add next_retry_at to async_operations for task-owned retry scheduling
+    op.execute(f"ALTER TABLE {schema}async_operations ADD COLUMN IF NOT EXISTS next_retry_at TIMESTAMPTZ NULL")
+
+    # Index for polling: status + next_retry_at
+    op.execute(
+        f"CREATE INDEX IF NOT EXISTS idx_async_operations_status_retry "
+        f"ON {schema}async_operations(status, next_retry_at)"
+    )
+
+
+def downgrade() -> None:
+    schema = _get_schema_prefix()
+    op.execute(f"DROP INDEX IF EXISTS {schema}idx_async_operations_status_retry")
+    op.execute(f"ALTER TABLE {schema}async_operations DROP COLUMN IF EXISTS next_retry_at")
+    op.execute(f"DROP INDEX IF EXISTS {schema}idx_webhooks_bank_id")
+    op.execute(f"DROP TABLE IF EXISTS {schema}webhooks")

hindsight-api/hindsight_api/alembic/versions/f7g8h9i0j1k2_add_webhook_http_config.py

@@ -0,0 +1,33 @@
+"""Add http_config JSONB column to webhooks table.
+
+Stores HTTP delivery configuration (method, timeout, headers, params) as a
+single JSONB column rather than separate columns.
+
+Revision ID: f7g8h9i0j1k2
+Revises: e4f5a6b7c8d9
+Create Date: 2026-03-04
+"""
+
+from collections.abc import Sequence
+
+from alembic import context, op
+
+revision: str = "f7g8h9i0j1k2"
+down_revision: str | Sequence[str] | None = "e4f5a6b7c8d9"
+branch_labels: str | Sequence[str] | None = None
+depends_on: str | Sequence[str] | None = None
+
+
+def _get_schema_prefix() -> str:
+    schema = context.config.get_main_option("target_schema")
+    return f'"{schema}".' if schema else ""
+
+
+def upgrade() -> None:
+    schema = _get_schema_prefix()
+    op.execute(f"ALTER TABLE {schema}webhooks ADD COLUMN IF NOT EXISTS http_config JSONB NOT NULL DEFAULT '{{}}'")
+
+
+def downgrade() -> None:
+    schema = _get_schema_prefix()
+    op.execute(f"ALTER TABLE {schema}webhooks DROP COLUMN IF EXISTS http_config")