refactor(taskctl): split pulse.ts and tool.ts — both exceed 500-line module limit

[randomm]

Problem

Both files added in the taskctl EPIC exceed AGENTS.md's 500-line hard limit:

• packages/opencode/src/tasks/pulse.ts: ~971 lines (limit: 500)
• packages/opencode/src/tasks/tool.ts: ~999 lines (limit: 500)

Suggested splits

pulse.ts → 3 modules

• pulse.ts — startPulse(), tick orchestration, lock file management (~200 lines)
• pulse-scheduler.ts — scheduleReadyTasks(), spawnDeveloper(), spawnAdversarial() (~250 lines)
• pulse-verdicts.ts — processAdversarialVerdicts(), commitTask(), respawnDeveloper(), escalateToPM() (~300 lines)

tool.ts → 2 modules

• tool.ts — Tool.define(), schema, dispatch router (~150 lines)
• tool-commands.ts — all 19 command handler implementations (~700 lines, still large but single responsibility)

Acceptance criteria

• Each file under 500 lines
• All exports preserved (no API changes)
• All existing tests still pass
• bun run typecheck passes with 0 errors