fix(dag): product audit batch — #378 #379 #380 #381

[LeXwDeX]

Summary

Delivers the four product-audit fixes as one unified delivery:

• fix(command): register /dag-template-update on the v1 command surface #378 register /dag-template-update on the v1 command surface (Command.Default + core DagTemplateUpdateContent export + registration test)
• fix(dag): pause must stop already-queued nodes from spawning #379 pause fence in the spawn fiber: a queued node no longer materializes its child session while the workflow is paused; it stays queued and spawns after resume (fail-open status read; adoption fence stays authoritative)
• fix(dag): resolve global dag-prompts from the configured config directory #380 global dag-prompts resolve through Flag.OPENCODE_CONFIG_DIR ?? Global.Path.config like every sibling global-asset lookup (redirect regression test included)
• fix(dag): extend must resume a paused workflow instead of stranding new nodes #381workflow extend mirrors replan: auto-resume a paused workflow after a successful extend and emit the pause/resume note (race-tolerant)

Verification

• bun test test/dag/ test/command/ — 610 pass; the only 3 failures (dag-node-supervision deadline-enforcement timeouts) also fail on clean main (verified via stash)
• bun typecheck clean; repo lint at 4850/4850 budget

Closes#378
Closes#379
Closes#380
Closes#381