fix(openviking): harden session sync and commit recovery

[kshitijk4poor]

Summary

Salvages #58871 with minor cleanup: dead parameters removed, lock-path assignment reordered, redundant exception branch collapsed, and per-turn marker re-writes eliminated.

Changes

• plugins/memory/openviking/init.py: removed dead current_sid param from _recover_pending_sessions; removed dead cleanup param from _release_owner_run_claim (always True); set _run_lock_path after flock succeeds; collapsed BlockingIOError branch into OSError+errno check; added _pending_marked_sids set to skip re-writing marker file on every sync_turn call
• tests/plugins/memory/test_openviking_provider.py: updated _recover_pending_sessions call (no args)

Attribution

• @ehz0ah — session commit recovery, orphan session recovery
• @NPFernando — OpenViking setup docs
• @ckorhonen — structured session sync batching

Validation

• 152/152 tests passed
• ruff clean, py_compile OK, no Windows footguns
• E2E real-import smoke test: plugin loads, path traversal blocked, signatures verified, no crashes
• git diff --check clean

Supersedes

• fix(openviking): commit orphaned sessions at startup when new CLI process takes over #31434 (orphan session commit at startup) — implemented inside provider lifecycle with advisory locks
• fix(cli): initialize session_id before OpenViking orphan commit #31493 (session_id init before orphan commit) — addressed by running recovery in initialize() after self._session_id is set

Closes #58871, #31434, #31493