Wire the issue oracle to real GitHub GraphQL

[ronimoe]

Context

issues.IssueOracle is a deterministic fake. Wire it to real closingIssuesReferences (verified link) + issue open-state, including the at-land recheck (the last statement before adv.advance).

Acceptance

V3 passes/fails against real issues; an issue closed between precheck and land aborts the land; oracle outage => NEEDS_HUMAN.

Seam

tools/conductor/issues.py, verifier.py (V3), the land-recorder at-land recheck.

[ronimoe]

Implemented in 967fe7f.

GitHubIssueOracle (issues.py) backs V3 with real GitHub GraphQL: closingIssuesReferences for the verified PR↔issue link plus issue open-state. Any failure (network / auth / rate limit) maps to UNKNOWN → NEEDS_HUMAN — fail closed, never a silent pass.

The at-land recheck (the last gate before the lease) is now wired: BatchEngine(at_land_guard=...) → record_land(guard=...). An issue closed between the V3 precheck and the land holds the batch (trunk not advanced) rather than landing — a precheck PASS can never substitute for the at-land check.

Unit-tested (test_gh_ports.py): oracle state/link parsing including outage→None, the recheck_at_land composition, and the engine holding on an at-land close vs landing when open. Remaining for full close: live validation against real issues (the default runner shells to gh api graphql).