feat: add generated scene skill platform hardening

docs/superpowers/specs/2026-04-19-g6-host-bridge-execution-semantics-design.md

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+# G6 Host-Bridge Execution Semantics Design
+
+> Date: 2026-04-19
+> Status: Draft
+> Upstream Report: [2026-04-19-g6-host-bridge-prerequisites-report.md](D:/data/ideaSpace/rust/sgClaw/claw-new/docs/superpowers/reports/2026-04-19-g6-host-bridge-prerequisites-report.md)
+
+## 1. Intent
+
+This design defines the next bounded slice after `G6 host-bridge prerequisites` isolates the minimum blocked capability.
+
+The target is:
+
+`G6 host-bridge execution semantics`
+
+## 2. Why This Slice
+
+This slice is selected because the remaining `G6` gap is narrower than broad host-runtime implementation:
+
+1. bridge action invocation semantics
+2. callback completion semantics
+
+## 3. Scope Boundary
+
+This design is limited to semantic scoping only.
+
+It may include:
+
+1. defining the minimum bridge action semantic
+2. defining the minimum callback completion semantic
+3. defining how those semantics bound later `G6` real-sample entry
+
+It must not include:
+
+1. implementing host-runtime directly
+2. executing a `G6` real sample
+3. opening `G8`
+4. reopening `G7`
+
+## 4. Target Outcome
+
+The bounded target outcome is one state:
+
+1. one bounded `G6 host-bridge execution semantics` plan
+
+## 5. Exit Condition
+
+This design is complete when implementation can be bounded to one plan that:
+
+1. freezes the semantic boundary
+2. separates bridge invocation from callback completion
+3. emits one bounded follow-up plan