fix(linkedin-studio): S1 hardening — method calibration (quick) + Start journey

Hardening phase S1. Tightened the hook character bound from one-sided
(under 140) to the full canonical 110-140 band across the Start-journey
creation surfaces, matching hooks/prompts/content-quality-gate.md:
- quick.md: hook band on Step 2 + Step 5 checklist; added a buzzword check
  and a 150-500 length-band check; checklist tally 6 -> 7.
- onboarding.md: hook band in Phase 3.2 + 3.3 (length + no-links already present).
- first-post.md: hook band in Step 4 + Step 5 (length + no-links already present).
- setup.md: zero-edit pass (all four axes already satisfied).

Adds docs/hardening/log.md (per-command audit trail, 5-step method) and
docs/hardening/review.md (cold /trekreview: ALLOW, 0 BLOCKER/0 MAJOR/1 MINOR).
Lint Failed:0, counts 29/19/25/6 unchanged. No structural/version churn.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

plugins/linkedin-studio/commands/quick.md

@@ -65,7 +65,7 @@ per-type structures and let them pick before applying the 3-line formula.
 
 Use this structure for all quick posts:
 
-**Line 1: Hook (under 140 characters)**
+**Line 1: Hook (110-140 characters)**
 - Creates curiosity or makes a statement
 - Must work standalone on mobile
 
@@ -137,13 +137,14 @@ Create the post, then verify:
 
 **Quick Quality Check (30 seconds):**
 - [ ] On-topic for my expertise? (Y/N)
-- [ ] Hook works in 140 chars? (Y/N)
+- [ ] Hook in the 110-140 band (not just under 140)? (Y/N)
 - [ ] Clear value delivered? (Y/N)
 - [ ] Ends with engagement prompt? (Y/N)
 - [ ] No external links in body? (Y/N)
-- [ ] Under 500 characters? (Y/N)
+- [ ] No corporate buzzwords? (Y/N)
+- [ ] In the 150-500 band (not just under 500)? (Y/N)
 
-**All 6 = Yes? -> Ready to post.**
+**All 7 = Yes? -> Ready to post.**
 
 ### De-AI / Differentiation Gate (fast)