[AZ-899] [AZ-900] [AZ-901] Baseline doc + retro gate + EVIDENCE_OUT fix

AZ-899: create _docs/02_document/architecture_compliance_baseline.md
seeded with 0 violations and the 2026-05-20 structural snapshot facts
(15 inventory entries, 0 import cycles, 5 contract files). Documents
the append-on-violation / mark-resolved-on-fix / snapshot-refresh
protocol so cumulative reviews can emit Baseline Delta sections.
Closes cycle-1 retro Top-3 #3 (third attempt).

AZ-900: codify LESSONS 2026-05-26 [process] in
.cursor/skills/autodev/flows/existing-code.md - Re-Entry After
Completion now hosts a Previous-Cycle Retro Existence Gate that
BLOCKS the cycle increment if no _docs/06_metrics/retro_*.md file
dated within [cycle_start, cycle_end] exists. Skipped on
state.cycle == 1. Presents Choose A (author retro) / B (stub +
leftover) / C (abort). state.md - Session Boundaries gains a
cross-reference bullet.

AZ-901: fix e2e/runner/conftest.py:56 EVIDENCE_OUT default - host
pytest now resolves <repo_root>/e2e-results/evidence/ instead of
/e2e-results/evidence (container-only path; crashed on macOS / non-
root Linux). Docker + Jetson harnesses unaffected (they pass
--evidence-out explicitly). Verified locally: 24 SKIPPED, exit 0,
evidence written. Closes leftover 2026-05-26_evidence_out_default_path.md.

Co-authored-by: Cursor <cursoragent@cursor.com>

_docs/02_tasks/done/AZ-899_architecture_compliance_baseline.md

@@ -0,0 +1,78 @@
+# Land `architecture_compliance_baseline.md` (cycle-3 retro #3, third try)
+
+**Task**: AZ-899_architecture_compliance_baseline
+**Name**: Create `_docs/02_document/architecture_compliance_baseline.md` so cumulative reviews can emit `## Baseline Delta` rows
+**Description**: Cycle-1 retro Top-3 Improvement Action #3, repeated in cycle-3 retro Top-3 #3. The file has been unmade across cycles 2 and 3, leaving cumulative reviews unable to quantify carried-over / resolved / newly-introduced architecture violations per cycle. Seed the baseline from `_docs/06_metrics/structure_2026-05-20.md` with `0` violations, freeze the snapshot semantics, and wire the existing-code flow's Step 2 to reference it.
+**Complexity**: 1 SP
+**Dependencies**: None (operates on existing artifact `_docs/06_metrics/structure_2026-05-20.md`)
+**Component**: documentation only — no source code change
+**Tracker**: AZ-899 (https://denyspopov.atlassian.net/browse/AZ-899)
+**Epic**: (none — cycle-4 process housekeeping)
+
+## Problem
+
+Cycle-3 retro § Structural Metrics:
+
+> `_docs/02_document/architecture_compliance_baseline.md` **still does not exist** — cycle-1 retro Top-3 Improvement Action #3 was NOT delivered in cycles 2 or 3.
+
+Without a baseline, cumulative reviews log "`_docs/02_document/architecture_compliance_baseline.md` does NOT exist → no Baseline Delta section emitted". Structural regressions (new cycles in the import graph, newly-introduced violations) therefore cannot be quantified across cycles — only verified pairwise per batch.
+
+## Outcome
+
+- Cumulative-review reports starting from cycle-4 batch 1 emit a `## Baseline Delta` section that quantifies new vs. resolved vs. carried-over architecture violations.
+- Cycle-end retros can compare structural deltas across cycles using a single canonical baseline document instead of re-deriving from the previous cycle's snapshot.
+
+## Scope
+
+### Included
+
+- Create `_docs/02_document/architecture_compliance_baseline.md` seeded with **0** violations.
+- Reference `_docs/06_metrics/structure_2026-05-20.md` as the source-of-truth snapshot from which the baseline was derived.
+- Document the file's update protocol: a new violation found in a cumulative review is appended (with batch ID, severity, finding ID); a resolution is recorded by marking the row `RESOLVED in batch <ID>`.
+- Document the snapshot-refresh trigger: any cycle that materially changes structure (component count, cross-component edges, new contracts) re-snapshots via `python -m gps_denied_onboard.tools.structure_snapshot` (or equivalent existing script — verify before reference).
+
+### Excluded
+
+- Refactoring source code to fix violations — none currently exist.
+- Adding new component scaffolding — out of scope.
+- Modifying `code-review` or `retrospective` skills — they already reference the file; the only change needed is making the referenced file exist.
+
+## Acceptance Criteria
+
+**AC-1: Baseline file exists with 0 violations**
+Given a fresh repo checkout
+When `ls _docs/02_document/architecture_compliance_baseline.md` runs
+Then the file exists and its `## Violations` section is explicitly empty (or marked "None at baseline")
+
+**AC-2: Baseline references the structural snapshot**
+Given the baseline file
+When read
+Then it includes a `## Source` section pointing at `_docs/06_metrics/structure_2026-05-20.md` and lists the structural facts (15 components, 0 import cycles, 5 contract files) that establish the "0 violations" claim
+
+**AC-3: Update protocol documented**
+Given the baseline file
+When read
+Then it includes an `## Update Protocol` section describing append-on-violation, mark-resolved-on-fix, and the snapshot-refresh trigger
+
+**AC-4: Cumulative-review hook verified**
+Given the baseline file in place
+When the cycle-4 first cumulative-review report is generated
+Then the report emits a `## Baseline Delta` section (even if empty: "0 new, 0 resolved, 0 carried-over")
+
+## Constraints
+
+- File format: markdown, matches the structure of `_docs/06_metrics/structure_2026-05-20.md` style.
+- No source code change permitted under this ticket — strictly documentation.
+
+## Risks & Mitigation
+
+**Risk 1: Future violations slip past the baseline**
+- *Risk*: A cumulative review finds a violation but the reviewer forgets to append it to the baseline.
+- *Mitigation*: The `code-review` skill (referenced in cycle-3 retro Suggested Updates) should be updated separately to auto-append; this ticket only delivers the baseline file. The follow-up belongs in cycle 5 if needed.
+
+## References
+
+- Cycle-3 retro: `_docs/06_metrics/retro_2026-05-26.md` § Top 3 Improvement Actions #3
+- Cycle-1 retro: `_docs/06_metrics/retro_2026-05-20.md` § Top 3 Improvement Actions #3 (original)
+- Source snapshot: `_docs/06_metrics/structure_2026-05-20.md`
+- Existing-code flow Step 2: `.cursor/skills/autodev/flows/existing-code.md` § "Step 2 — Architecture Baseline Scan"