fix: reuse opencode control session across orch-monitor --new

[proboscis]

Summary

• Add retry/backoff session lookup in getOrCreateOpenCodeControlSession() so transient opencode server restarts during orch-monitor --new do not immediately force a new control session.
• Make recovery more robust by normalizing directories (clean + symlink resolution) and adding a global title-based fallback (orch-control) when directory-scoped lookup cannot recover.
• Add explicit daemon log reasons for reuse/recovery failures and extend daemon tests for retry behavior, global fallback recovery, path normalization, and fresh-session creation.

Testing

• go test -v ./internal/daemon -run "TestGetOrCreateOpenCodeControlSession(ReusesExisting|CreatesNewWhenNoStoredSession|RetriesLookupBeforeReuse|RecoversAfterServerRestart|RecoversFromGlobalListWhenDirectoryLookupEmpty|CreatesWhenRecoveryFindsNoSession)|TestFindBestOpenCodeControlSessionNormalizesProjectRootPath" -count=1
• go test ./internal/daemon -count=1
• go build ./...

Acceptance Criteria Evidence

• orch-monitor --new preserves control session history when opencode server is still running
  • Verified by TestGetOrCreateOpenCodeControlSessionReusesExisting
  • Verified by TestGetOrCreateOpenCodeControlSessionRetriesLookupBeforeReuse (transient not-found before successful reuse)
• Session reuse works even if paths differ by trailing slash or symlink resolution
  • Verified by TestFindBestOpenCodeControlSessionNormalizesProjectRootPath (symlink root + trailing slash)
• --new-control-agent still correctly creates a fresh session
  • Verified by TestGetOrCreateOpenCodeControlSessionCreatesNewWhenNoStoredSession (no stored session => direct fresh create path)
• Add daemon log messages when session reuse fails (with reason) for debuggability
  • Verified by TestGetOrCreateOpenCodeControlSessionCreatesWhenRecoveryFindsNoSession (asserts failure-reason log output)
• Add test for path normalization in findBestOpenCodeControlSession()
  • Added TestFindBestOpenCodeControlSessionNormalizesProjectRootPath

Refs: orch-440