harden(skills): SDD proportionality resists over-use; pipeline consumes cited specs

Adversarial + consistency review findings (B1, B2, B3, B5, F1):
- Red Flags line read literally licensed skipping reviews on trivial
  tasks INSIDE multi-task plans; now states the only exception is a
  whole-plan trivial change and never-skip within multi-task plans.
- "a one-line edit" example blessed one-line behavioral changes
  (e.g. adding "|| user.isOwner"); dropped. Trivial is now defined as
  a property of the diff (no logic/control-flow/behavior change), not
  of the plan's self-description. The "nothing for review to catch"
  justification proved too much; replaced with the cost argument.
- "verify it" was undefined on the trivial path; now concrete (run
  tests/command, confirm output, verification-before-completion).
- Flowchart diamond now matches the prose: "fully-specified" + "any
  doubt = no" (the failing agents execute the flowchart literally).
- New Spec Context section + prompt-template updates: the controller
  reads the spec cited in the plan header and pastes cited sections
  into implementer/spec-reviewer prompts; the spec reviewer's
  diff-only rule gets a spec-document exception. Without this, the
  stack's reference-not-restate rule starves the SDD pipeline of
  requirements.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

skills/subagent-driven-development/implementer-prompt.md

@@ -12,6 +12,8 @@ Subagent (general-purpose):
 
     [FULL TEXT of task from plan - paste it here, don't make subagent read file]
 
+    [If the task cites spec sections, paste the cited sections' text here too — the plan references requirements rather than restating them]
+
     ## Context
 
     [Scene-setting: where this fits, dependencies, architectural context]