fix(task-board): resolve the conflict auto-resolve gate from the board's own lanes

[pedrofrxncx]

Same bug class as #6849 and #6854 ("advanceToReviewIfInProgress" and the failed-run reaction both hardcoded a Studio lane literal instead of reading the org board's own column), found in the conflict auto-resolve path this time.

TASK_BOARD_ITEM_PRS_GET's conflict auto-resolve trigger compared item.status === "in_review", and reactToApprovedPrConflict's own entry gate compared item.status !== "in_review" — both against the literal Studio uses, even though reactToApprovedPrConflict already fetches boardLanes(ctx, orgId) a few lines later and uses lanes.review/lanes.progress everywhere else in the same function. On an org-owned board (org_board_columns) whose In Review column is named anything else, both comparisons never match: an approved PR that develops a merge conflict with its base branch is never auto-handed back to the Super Agent to resolve — it just sits there, silently, forever.

Fix: hoist the boardLanes fetch in both files and compare against lanes.review instead of the literal. In conflict-reaction.ts the guard is also pulled out into a small pure isConflictResolutionCandidate helper, matching the file's existing "Pure — unit-tested" pattern, so the org-lane case is covered without a database.

No behavior change for Studio's own board: STUDIO_LANES.review is still the literal "in_review", so lanes.review resolves to the same value there.

To confirm: bun test apps/api/src/tools/task-board/conflict-reaction.test.ts (9 pass, including the new org-lane cases), plus cd apps/api && bunx tsc --noEmit and bunx oxlint on the three changed files, all clean locally. Full CI validates the rest.

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Summary by cubic

Fixes the conflict auto-resolve gate so it checks the board's own In Review column instead of Studio's hardcoded "in_review" literal. On org-owned boards with a renamed In Review column, approved PRs with merge conflicts were never auto-handed back to the Super Agent; they now are.

• Extracts the entry gate in conflict-reaction.ts into a pure isConflictResolutionCandidate helper, unit-tested for the org-lane case.
• No behavior change for Studio's own board, where the review lane still resolves to "in_review".

^{Written for commit 8a757e0. Summary will update on new commits.}