[TheGreatAxios]

Summary

Removes dead config, an unreachable branch, and an inert alias from the session compactor (CL-10511). One item deviated (kept) because a real consumer exists — see below.

Changes

1. maxAnchorTurns config (field + default + record entry) — Verified inert: no code reads it as a behavior input (grep over the repo shows it only copied into the output record.parameters, never consumed; no test asserts on it). Removed the field from CompactorConfig, its DEFAULT_COMPACTOR_CONFIG default, and the record.parameters.maxAnchorTurns entry. Mechanically dropped the now-invalid maxAnchorTurns: keys from compactor-pairing.test.ts (×13), context-compactor.test.ts (×7), and compaction-archive.test.ts (×1) so tsc --noEmit stays green.
2. buildTurnSummary anchorCount param + unreachable branch — Verified inert: every call site omits it or passes 0 (production caller compactor.ts omits; context-compactor.test.ts omits; compactor-pairing.test.ts passed 0). Removed the param and the anchorCount > 0 ? … : "" branch; dropped the explicit 0 argument at compactor-pairing.test.ts:211.
3. compactorNoOpFloor() → const COMPACT_NOOP_FLOOR = 1 — DEVIATION, not performed. The function is not inert: src/agent/compaction.ts imports it and uses it as MIN_TURNS_TO_COMPACT (a production behavior input that arms the compaction governor), and 4 test files call it. Removing/replacing it would require touching files outside this ticket's scope, so per the ticket rules it is left in place and reported as a deviation.
4. isCompactSpacerTurn alias — Verified inert: private one-line alias for isHarnessCompactSpacer, with all 3 call sites inside compactor.ts (no external consumers). Inlined the call sites and deleted the alias.

Verification

• bun test ./src/session/compactor-pairing.test.ts ./src/session/compaction-archive.test.ts ./src/context-compactor.test.ts — 70 pass, 0 fail.
• bun run typecheck (tsc --noEmit) — passes.
• oxfmt --check + oxlint on the 4 changed files — clean.
• Diff: 4 files changed, 5 insertions(+), 35 deletions(-).

Fixes CL-10511

Plan: https://linear.app/abklabs/issue/CL-10511/remove-dead-code-and-inert-aliases-in-session-compactor

[linear-code]

CL-10511

[corbits-triage]

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