feat: fold project-scoped memories into context pack

The retrieval-quality review on 2026-04-11 found that active
project/knowledge/episodic memories never reached the pack: only
Trusted Project State and identity/preference memories were being
assembled. Reinforcement bumped confidence on memories that had
no retrieval outlet, so the reflection loop was half-open.

This change adds a third memory tier between identity/preference
and retrieved chunks:

- PROJECT_MEMORY_BUDGET_RATIO = 0.15
- Memory types: project, knowledge, episodic
- Only populated when a canonical project is in scope — without
  a project hint, project memories stay out (cross-project bleed
  would rot the signal)
- Rendered under a dedicated "--- Project Memories ---" header
  so the LLM can distinguish it from the identity/preference band
- Trim order in _trim_context_to_budget: retrieval → project
  memories → identity/preference → project state (most recently
  added tier drops first when budget is tight)

get_memories_for_context gains header/footer kwargs so the two
memory blocks can be distinguished in a single pack without a
second helper.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

tests/test_context_builder.py

@@ -251,3 +251,60 @@ def test_unknown_hint_falls_back_to_raw_lookup(tmp_data_dir, sample_markdown, mo
 
     pack = build_context("status?", project_hint="orphan-project", budget=2000)
     assert "Solo run" in pack.formatted_context
+
+
+def test_project_memories_included_in_pack(tmp_data_dir, sample_markdown):
+    """Active project-scoped memories for the target project should
+    land in a dedicated '--- Project Memories ---' band so the
+    Phase 9 reflection loop has a retrieval outlet."""
+    from atocore.memory.service import create_memory
+
+    init_db()
+    init_project_state_schema()
+    ingest_file(sample_markdown)
+
+    mem = create_memory(
+        memory_type="project",
+        content="the mirror architecture is Option B conical back for p04-gigabit",
+        project="p04-gigabit",
+        confidence=0.9,
+    )
+    # A sibling memory for a different project must NOT leak into the pack.
+    create_memory(
+        memory_type="project",
+        content="polisher suite splits into sim, post, control, contracts",
+        project="p06-polisher",
+        confidence=0.9,
+    )
+
+    pack = build_context(
+        "remind me about the mirror architecture",
+        project_hint="p04-gigabit",
+        budget=3000,
+    )
+    assert "--- Project Memories ---" in pack.formatted_context
+    assert "Option B conical back" in pack.formatted_context
+    assert "polisher suite splits" not in pack.formatted_context
+    assert pack.project_memory_chars > 0
+    assert mem.project == "p04-gigabit"
+
+
+def test_project_memories_absent_without_project_hint(tmp_data_dir, sample_markdown):
+    """Without a project hint, project memories stay out of the pack —
+    cross-project bleed would rot the signal."""
+    from atocore.memory.service import create_memory
+
+    init_db()
+    init_project_state_schema()
+    ingest_file(sample_markdown)
+
+    create_memory(
+        memory_type="project",
+        content="scoped project knowledge that should not leak globally",
+        project="p04-gigabit",
+        confidence=0.9,
+    )
+
+    pack = build_context("tell me something", budget=3000)
+    assert "--- Project Memories ---" not in pack.formatted_context
+    assert pack.project_memory_chars == 0