refactor: decompose append.py and effects.py by semantic concern (BTND-07-004)

[sei-ahouseholder]

Summary

• append.py (499 lines, 7 classes) → append/ subpackage: conditions.py (4 guard nodes + _has_status_in_participant helper), actions.py (3 mutating nodes), __init__.py (re-exports all 7 public names)
• effects.py (495 lines, 4 classes) → 4 per-class files (participant_status_effect.py, note_effect.py, invite_accept_effect.py, close_case_effect.py) + _helpers.py (_LedgerEffectNode base + _extract_id_from_field) extracting shared DRY pattern
• All importers updated in-place; no backward-compatibility shims
• Test structure mirrored; adds TestCheckParticipantRMNotClosedNode (previously untested) and tests for the 3 previously untested effects.py nodes

What changed

Before	After
status/nodes/append.py (499 lines)	status/nodes/append/conditions.py + actions.py + __init__.py
sync/nodes/effects.py (495 lines)	_helpers.py + 4 per-class files
test_append.py	append/conftest.py + test_conditions.py + test_actions.py
test_effects.py	4 per-class test files

DRY extractions

• _LedgerEffectNode base class extracted from the 4 effects.py nodes — all had identical setup() (register activity blackboard key) and _require_log_entry call pattern
• _has_status_in_participant() helper in append/conditions.py
• _extract_id_from_field() moved from effects.py to _helpers.py

Out of scope — 5 other near-limit modules

replay.py (498), suggest_actor/emit.py (498), deploy_fix.py (497), embargo/nodes/lifecycle.py (494), conditions.py (488).

Test plan

• uv run pytest test/core/behaviors/status/nodes/append/ — 18 passed
• uv run pytest test/core/behaviors/sync/nodes/test_*_effect.py — 13 passed
• uv run pytest test/core/ test/wire/ test/adapters/ — all passed
• uv run flake8 — clean
• uv run pyright on all new/modified files — 0 errors

Closes #2269

🤖 Generated with Claude Code

[sei-ahouseholder]

PR Triage: #2282 — refactor: decompose append.py and effects.py by semantic concern (BTND-07-004)

Linked issues: #2269 (BTND-07-004's 500-line ceiling is forcing unrelated decomposition churn — append.py and effects.py both at the limit)
Changed files: 22 files — core/behaviors/status, core/behaviors/sync
CI status: ⚠️ unit tests ✅ passing · demo integration ❌ pre-existing failures on main (engage_case event type — unrelated to this PR)
Merge state: ❌ CONFLICTING (DIRTY)
Base branch: main
Needs integration tests: yes

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Findings

#	Phase	Severity	Description	Outcome
phase12-merge-conflict-0	merge-state	❌ FAIL	Branch has conflicts with main — cannot merge until resolved	fix-now
phase3-closes-not-at-top-0	pr-body-format	⚠️ IMPROVE	Closes #2269 is at the bottom of the PR body; must be the first line before any ## header (pr-body-guide.md)	fix-now
phase9-stale-docstring-ref-0	notes-docs-currency	⚠️ IMPROVE	leave.py:22 docstring still references deleted sync.nodes.effects.ApplyCloseCaseFromLedgerNode; correct path is sync.nodes.close_case_effect.ApplyCloseCaseFromLedgerNode	fix-now

Total: 1 FAIL · 2 IMPROVE · 0 NEW-ISSUE

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Notes

• BTND-07 structure test: 93/93 passed. All new modules are ≤ 329 lines. ✓
• __init__.py re-exports all 7 public names from append/ subpackage. ✓
• sync/nodes/__init__.py re-exports all effect node names from per-class files. ✓
• No backward-compatibility shims (per doctrine). ✓
• notes/structured-logging.md updated to reference close_case_effect.py. ✓
• No ADR warranted — pure structural decomposition, no architectural change. ✓
• Demo CI failures (engage_case event type missing in fvcv-handoff, fcvcv, fcv-reject, fv) are pre-existing on all recent main runs and are unrelated to this PR.

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Triage artifact: .claude/pr-2282-triage.json
Next step: /pr-execute will resolve the merge conflict, move the Closes line, and fix the stale docstring.