feat: add generated scene skill platform hardening

docs/superpowers/specs/2026-04-19-timeout-budget-rerun-hygiene-design.md

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+# Timeout Budget and Rerun Hygiene Design
+
+> Date: 2026-04-19
+> Status: Draft
+> Upstream Diagnostic: `docs/superpowers/reports/2026-04-19-timeout-regression-diagnostic-report.md`
+
+## Intent
+
+Prevent budget-sensitive scenes from being miscounted as `source-unreadable` when they can resolve into:
+
+1. `executed-pass`
+2. structured `fail-closed`
+
+under a bounded rerun budget.
+
+This design does not attempt to improve scene understanding. It only changes timeout handling and rerun classification hygiene.
+
+## Problem Statement
+
+The timeout regression diagnostic produced:
+
+| Scene id | Diagnostic label | Actual behavior under `90s` |
+| --- | --- | --- |
+| `sweep-015-scene` | `timeout-rerun-pass` | completed successfully |
+| `sweep-025-scene` | `timeout-rerun-pass` | completed successfully |
+| `sweep-040-scene` | `timeout-rerun-fail-closed` | resolved into structured fail-closed |
+
+This means the current fixed `45s` budget is too coarse for a subset of scenes. It collapses:
+
+1. budget-sensitive success
+2. budget-sensitive fail-closed
+3. true unreadable or hanging cases
+
+into the same `source-unreadable` bucket.
+
+## Scope
+
+In scope:
+
+1. define a bounded timeout-budget policy
+2. define when a diagnostic rerun is allowed
+3. define how rerun results should be classified
+4. define output JSON and report for timeout hygiene verification
+
+Out of scope:
+
+1. analyzer logic changes
+2. generator contract recovery changes
+3. scene promotion
+4. execution board updates
+5. full `102` sweep improvement work
+6. timeout implementation unrelated to rerun hygiene
+
+## Policy
+
+### Primary Sweep Budget
+
+The initial sweep still runs with the fixed primary budget.
+
+### Secondary Diagnostic Budget
+
+When a scene ends with:
+
+1. `source-unreadable`
+2. reason `generator timeout after 45s`
+
+it becomes eligible for one bounded rerun under a secondary timeout budget.
+
+### Rerun Result Mapping
+
+A bounded rerun may only map to:
+
+1. `timeout-rerun-pass`
+2. `timeout-rerun-fail-closed`
+3. `timeout-rerun-timeout`
+4. `timeout-rerun-error`
+
+These are hygiene classifications, not promoted scene statuses.
+
+### Board and Promotion Boundary
+
+Even when rerun succeeds:
+
+1. do not update `scene_execution_board_2026-04-18.json`
+2. do not convert the scene to promoted status
+3. do not silently merge the rerun result into canonical scene status
+
+## Output
+
+1. `tests/fixtures/generated_scene/timeout_budget_rerun_hygiene_2026-04-19.json`
+2. `docs/superpowers/reports/2026-04-19-timeout-budget-rerun-hygiene-report.md`
+
+## Success Criteria
+
+1. timeout scenes are no longer treated as a single unreadable bucket in the hygiene layer
+2. rerun-pass and rerun-fail-closed are distinguishable
+3. true timeout cases remain distinguishable
+4. no analyzer or generator implementation changes are made
+5. no execution board updates are made