feat(localtaskstore): add durable local state for task receipt, outbox, and restart recovery

[iAziz786]

Summary

Add a durable local task store under HOSTLINK_STATE_PATH that persists received, running, final, and interrupted task execution state. This establishes the persistence boundary required for reliable WebSocket reconnect, resend, and restart behavior before task result delivery can be trusted in production.

Changes

New package: app/services/localtaskstore/

• Configurable SQLite-backed store with spool cap (64MiB default) and terminal reserve (1MiB default)
• Two-table schema: local_task_executions (task/execution state keyed by task_id + execution_attempt_id) and local_task_outbox_messages (unacked output chunk / final result resend queue)
• RecordReceived, RecordStarted, AppendOutputChunk, RecordFinal, AckMessage, UnackedMessages, Snapshot, MarkInterruptedRunningTasks operations
• Oldest-first chunk rotation under spool cap with truncation markers
• Terminal result preserved under cap pressure
• Admission control: RecordReceived fails with ErrTerminalReserveUnavailable when outbox cannot reserve space for a future final result
• Startup recovery: stale running tasks converted to interrupted terminal records with synthetic outbox message
• Narrow extension interfaces: ReceiptStore, ResultOutbox, RecoveryStore
• Comprehensive temp-dir crash/restart persistence tests

Modified: config/appconf/

• LocalTaskStorePath() — derives default from HOSTLINK_STATE_PATH or explicit env override
• LocalTaskStoreSpoolCapBytes() — env HOSTLINK_LOCAL_STORE_SPOOL_CAP_BYTES, default 64MiB
• LocalTaskStoreTerminalReserveBytes() — env HOSTLINK_LOCAL_STORE_TERMINAL_RESERVE_BYTES, default 1MiB

Modified: main.go

• recoverLocalTaskStore() helper: opens store via NewDefault() and runs MarkInterruptedRunningTasks() on boot
• Store initialized in goroutine after server start, does not block registration, polling, heartbeat, metrics, or self-update

Verification

All tests pass:

• go test ./config/appconf/
• go test ./app/services/localtaskstore/
• go test . (root startup wiring tests)
• go test ./app/jobs/taskjob ./app/services/taskreporter/