docs(research): A6.P1 — capture directory structure + findings stub

Creates the 9 per-scenario capture directories (gitkeep stubs) and
the findings doc stub at docs/research/2026-05-21-a6-cdb-capture-findings.md.
A6.P1 fills the capture log slots (Task 15, user-driven); A6.P2
fills the analysis tables and findings section.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

docs/research/2026-05-21-a6-cdb-capture-findings.md

@@ -0,0 +1,74 @@
+# A6.P1 cdb capture findings — 2026-05-21
+
+**Status:** STUB — captures in progress. Tables filled by A6.P2 analysis.
+
+**Spec:** [`docs/superpowers/specs/2026-05-21-phase-a6-indoor-physics-fidelity-design.md`](../superpowers/specs/2026-05-21-phase-a6-indoor-physics-fidelity-design.md).
+
+**PDB match verification:** [`pdb-match-verification.txt`](2026-05-21-a6-captures/pdb-match-verification.txt).
+
+## Capture inventory
+
+| Scenario | Tag | Retail log | acdream log | Status |
+|---|---|---|---|---|
+| 1 | scen1_inn_doorway | [retail.log](2026-05-21-a6-captures/scen1_inn_doorway/retail.log) | [acdream.log](2026-05-21-a6-captures/scen1_inn_doorway/acdream.log) | pending |
+| 2 | scen2_inn_stairs | [retail.log](2026-05-21-a6-captures/scen2_inn_stairs/retail.log) | [acdream.log](2026-05-21-a6-captures/scen2_inn_stairs/acdream.log) | pending |
+| 3 | scen3_inn_2nd_floor | [retail.log](2026-05-21-a6-captures/scen3_inn_2nd_floor/retail.log) | [acdream.log](2026-05-21-a6-captures/scen3_inn_2nd_floor/acdream.log) | pending |
+| 4 | scen4_cottage_cellar | [retail.log](2026-05-21-a6-captures/scen4_cottage_cellar/retail.log) | [acdream.log](2026-05-21-a6-captures/scen4_cottage_cellar/acdream.log) | pending |
+| 5 | scen5_sewer_entry | [retail.log](2026-05-21-a6-captures/scen5_sewer_entry/retail.log) | [acdream.log](2026-05-21-a6-captures/scen5_sewer_entry/acdream.log) | pending |
+| 6 | scen6_sewer_first_stair | [retail.log](2026-05-21-a6-captures/scen6_sewer_first_stair/retail.log) | [acdream.log](2026-05-21-a6-captures/scen6_sewer_first_stair/acdream.log) | pending |
+| 7 | scen7_sewer_inter_room | [retail.log](2026-05-21-a6-captures/scen7_sewer_inter_room/retail.log) | [acdream.log](2026-05-21-a6-captures/scen7_sewer_inter_room/acdream.log) | pending |
+| 8 | scen8_sewer_chamber | [retail.log](2026-05-21-a6-captures/scen8_sewer_chamber/retail.log) | [acdream.log](2026-05-21-a6-captures/scen8_sewer_chamber/acdream.log) | pending |
+| 9 | scen9_sewer_corridor | [retail.log](2026-05-21-a6-captures/scen9_sewer_corridor/retail.log) | [acdream.log](2026-05-21-a6-captures/scen9_sewer_corridor/acdream.log) | pending |
+
+## Analysis tables (filled by A6.P2)
+
+### Table 1 — Per-site push-back delta
+
+*Placeholder — filled by A6.P2 analysis. Rows = (site × scenario) cross-product.
+Delta computed as `‖output_center − input_center‖` per call. Bug candidate
+threshold: ratio > 3× retail.*
+
+| Site | Scenario | Retail mean delta (mm) | Retail p99 (mm) | acdream mean (mm) | acdream p99 (mm) | Ratio |
+|---|---|---|---|---|---|---|
+
+### Table 2 — Path-frequency diff
+
+*Placeholder — filled by A6.P2 analysis. Paths labeled 1-7 per the
+find_collisions dispatcher.*
+
+| Scenario | Path | Retail count | acdream count | Diff % |
+|---|---|---|---|---|
+
+### Table 3 — ContactPlane lifecycle diff
+
+*Placeholder — filled by A6.P2 analysis.*
+
+| Scenario | Retail CP writes/sec | acdream CP writes/sec | Retail CP-restore-from-LKCP/sec | acdream CP-restore/sec |
+|---|---|---|---|---|
+
+### Table 4 — Sub-step state mutations
+
+*Placeholder — filled by A6.P2 analysis. Fields: cell_array_valid,
+hits_interior_cell, walk_interp, walkable, collide.*
+
+| Scenario | Field | Retail mutations/sec | acdream mutations/sec |
+|---|---|---|---|
+
+## Per-scenario narrative (filled by A6.P2)
+
+### Scenario 1 — Inn doorway entry
+
+*Placeholder.*
+
+### Scenario 2 — Inn stairs ascent
+
+*Placeholder.*
+
+*(etc. — 3 through 9)*
+
+## Findings (filled by A6.P2)
+
+*Numbered bug candidates. Each entry contains: title, retail decomp
+anchor (line in acclient_2013_pseudo_c.txt), our suspect code site
+(file + line), divergence quantified, proposed fix sketch, scenarios
+affected.*