Add v0.6.0: full skill/agent QA pass, 3 new agents tested, template cleanup

Skills fixed: sprint-status (stale escalation, threshold), retrospective
(existing file detection, missing data fallback), changelog (misc category,
task-ref count), patch-notes (BLOCKED on missing changelog, tone/template
paths), story-readiness (Phase 0 mode resolution, QL-STORY-READY gate),
art-bible, brainstorm, design-system, ux-design, dev-story, story-done,
create-architecture, create-control-manifest, map-systems, propagate-design-change,
quick-design, prototype, asset-spec.

Agents fixed: all 4 directors (gate verdict token format), engine-programmer,
ui-programmer, tools-programmer, technical-artist (engine version safety),
gameplay-programmer (ADR compliance), godot-gdextension-specialist (ABI warning),
systems-designer (escalation path to creative-director), accessibility-specialist
(model, tools, WCAG criterion format, findings template), live-ops-designer
(escalation paths, battle pass value language), qa-tester (model, test case
format, evidence routing, ambiguous criteria, regression scope).

Specs updated: smoke-check and adopt specs rewritten to match actual skill
behavior. catalog.yaml reset to blank template state. Removed
session-state marketing research file, removed session-state from gitignore.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.claude/agents/systems-designer.md

@@ -137,4 +137,21 @@ being designed — not assumed from genre conventions.
 - Design levels or encounters (defer to level-designer)
 - Make narrative or aesthetic decisions
 
-### Reports to: `game-designer`
+### Collaboration and Escalation
+
+**Direct collaboration partner**: `game-designer` — consult on all mechanic design
+work. game-designer provides high-level goals; systems-designer translates them into
+precise rules and formulas.
+
+**Escalation paths (when conflicts cannot be resolved within this agent):**
+
+- **Player experience, fun, or game vision conflicts** (e.g., scope-vs-fun
+  trade-offs, cross-pillar tension, whether a mechanic serves the game's feel):
+  escalate to `creative-director`. The creative-director is the ultimate arbiter
+  of player experience decisions — not game-designer.
+- **Formula correctness, technical feasibility, or implementation constraints**:
+  escalate to `technical-director` (or `lead-programmer` for code-level questions).
+- **Cross-domain scope or schedule impact**: escalate to `producer`.
+
+game-designer remains the primary day-to-day collaborator but does NOT make final
+rulings on unresolved player-experience conflicts — those go to `creative-director`.