Feat/issue 72 replication plugin

[jeid12]

Purpose

Implements a replication plugin that pulls data from the configured external source into internal Durable Object SQLite on a schedule, enabling close-to-edge read replicas.

Closes #72
/claim #72

Tasks

• Add new ReplicationPlugin with task management endpoints
• Add internal replication task table (tmp_replication_tasks) and cursor state
• Implement cursor-based pull (cursor_column + cursor_value) from external source
• Implement write path into internal source with INSERT OR REPLACE
• Support per-task interval and batch size controls
• Trigger replication execution via Durable Object alarm callback route
• Add replication alarm continuation in Durable Object alarm()
• Register plugin in worker startup plugin list
• Add plugin unit tests
• Add plugin README usage guidance

Verify

• Run tests:

pnpm vitest run \
  plugins/replication/index.test.ts \
  src/do.test.ts \
  src/handler.test.ts

• Manual flow:

# Create replication task
curl --location --request POST 'https://starbasedb.YOUR-ID-HERE.workers.dev/replication/tasks' \
  --header 'Authorization: Bearer ABC123' \
  --header 'Content-Type: application/json' \
  --data '{
    "sourceTable":"orders",
    "targetTable":"orders",
    "cursorColumn":"id",
    "intervalSeconds":60,
    "batchSize":500
  }'

# List tasks
curl --location 'https://starbasedb.YOUR-ID-HERE.workers.dev/replication/tasks' \
  --header 'Authorization: Bearer ABC123'

# Run once manually
curl --location --request POST 'https://starbasedb.YOUR-ID-HERE.workers.dev/replication/tasks/TASK_ID/run' \
  --header 'Authorization: Bearer ABC123'

# Delete task
curl --location --request DELETE 'https://starbasedb.YOUR-ID-HERE.workers.dev/replication/tasks/TASK_ID' \
  --header 'Authorization: Bearer ABC123'

Before

No built-in plugin mechanism to regularly pull selected external tables into internal SQLite for edge-local reads.

After

Replication tasks can be configured per table with interval + cursor strategy, and are executed on schedule through DO alarms.

Demo Video