Delete never-edited/never-acted/no-ship salvage classes (CL-6994)

[TheGreatAxios]

Summary

• Re-applies CL-6994's deletion on current origin/main (post CL-6946 part 2: delete prose-based sub-agent stop-reason matchers #610 structured stop reasons, post Delete repetition detection outright (CL-6995) #612 repetition/no-progress removal), replacing the earlier PR Delete never-edited/never-acted/no-ship/no-progress salvage classes #611 which had drifted into 9-file conflicts.
• Deletes HARD_BLOCK_SALVAGES / isHardBlockSalvage and the fingerprint-refusal branch in admit() — task re-dispatch of an identical brief is never refused now. admit() always succeeds; turn-budget salvage still throttles repeated same-brief retries via dispatchCount.
• Deletes the never-edited, never-acted, and no-ship stop reasons/salvage classes end-to-end: ForcedStopReason/SubAgentStopReason, evaluateSubAgentStop's everHadToolCalls/requireEdit branches, the requireEdit plumbing through nudge-director.ts/run.ts, and their parent hints/summaries in stop-policy.ts.
• Deletes task-tool.ts's dead recordRefusal/refusalLog path.
• Deletes the shell-write half of shell-evidence.ts (SHELL_WRITE_PROGRAMS, in-place-flag handling, redirection tracking) — read detection for the requireEvidence/CritiqueDirector gate is unchanged.
• Deletes thrash.ts's shell-write contribution to editedPaths; the typed-tool contribution stays as interventions.jsonl diagnostics only, feeding no stop decision.
• Dead-by-consequence found and removed: src/agent/director.ts's entire hard-block salvage nudge subsystem (salvageNudgeFired, pendingSalvageNudge, applySalvageNudge, pendingTaskCallIds) and src/agent/look-tour.ts (PRIMARY_SALVAGE_NUDGE) — both existed solely to nudge the parent after a hard-block salvage, which no longer exists.
• Rewrote/deleted tests asserting the deleted classes fire; kept coverage for turn-budget/cancelled/deadline/incomplete-report paths.
• CHANGELOG entry under ## [Unreleased].

Net: -511 lines (111 insertions, 622 deletions across 17 files).

Test plan

• bun run check (lint, typecheck, build, test) green — 5323 pass, 0 fail.

[linear-code]

CL-6994