feat(openviking-plugin): native Session+Search integration with memory-first retrieval and observable fallback

[mczabca-boop]

Summary

This PR integrates TinyClaw with OpenViking native architecture (Session + Memory + Search), while keeping a safe rollback path to legacy markdown retrieval/writeback.

This PR is stacked on #1 and functionally continues the OpenViking direction from TinyAGI#127.

What this PR adds

• Native OpenViking session lifecycle as primary write path
  • Create/reuse session
  • Write user/assistant messages to session
  • Commit on reset/session-end
• Native OpenViking search as primary prefetch path
  • Prefer typed retrieval from memory/resource/skill
  • Memory-first composition for injected context
  • Structured short snippets instead of large raw turn blocks
• Persistent local session mapping
  • (channel, senderId, agentId) -> openviking_session_id
• Compatibility fallback retained
  • Legacy markdown (active.md / closed/*.md) remains available and explicitly logged
• Better observability
  • Session write/commit success/failure logs
  • Retrieval hit distribution by type
  • Explicit fallback reason logging
  • Native prefetch dump for debugging (prefetch_dump_native_latest.txt)

Setup and runtime improvements

• Setup flow improved for OpenViking usage
  • OpenViking enablement flow in setup
  • OpenViking config bootstrap updates
  • OpenAI-based OpenViking path emphasized in current flow
• Startup/runtime hardening
  • OpenViking startup checks and safer defaults
  • Timeout handling improvements for prefetch/commit paths

Key files touched

• src/queue-processor.ts
• src/tools/openviking-tool.ts
• src/lib/openviking-prefetch.ts
• src/lib/openviking-session-map.ts
• lib/templates/agent-tools/openviking/openviking-tool.js
• lib/setup-wizard.sh
• lib/daemon.sh

Compatibility / rollback

• Feature flags keep rollback straightforward:
  • TINYCLAW_OPENVIKING_SESSION_NATIVE=1
  • TINYCLAW_OPENVIKING_SEARCH_NATIVE=1
  • TINYCLAW_OPENVIKING_PREFETCH=1
  • TINYCLAW_OPENVIKING_AUTOSYNC=1
• Disabling native flags falls back to prior behavior.

Validation notes

• Build passes (npm run build:main)
• End-to-end tests verified:
  • Session resolve/write/commit logs present
  • Native search hits include memory/resource/skill distribution
  • Reset + post-reset factual recall works from retrieved context
  • Fallback path remains explicit and observable

Risk / follow-up

• OpenViking commit/prefetch latency can vary by environment; timeout tuning may still be needed.
• Once hardening: gate plugins, add hook timeouts, and sanitize metadata #1 merges, this PR diff should collapse to the OpenViking-specific incremental changes.