fix: enforce durable memory in mosaic memory dir, not runtime-native silos

MEMORY.md was conditionally loaded so agents defaulted to their native
memory locations (e.g. ~/.claude/projects/*/memory/). This caused durable
learnings to be siloed per-runtime instead of shared across agents.

- Move MEMORY.md to mandatory load order in AGENTS.md (position 7)
- Add Memory Override section to all three runtime configs (Claude, Codex,
  OpenCode) explicitly forbidding native memory silos for durable data
- Add memory/ directory with .gitkeep to bootstrap source
- Add mkdir -p for memory/ in install.sh post-sync step

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

AGENTS.md

@@ -14,8 +14,9 @@ Before responding to any user message, you MUST read these files in order:
 4. `~/.config/mosaic/AGENTS.md`
 5. `~/.config/mosaic/TOOLS.md`
 6. `~/.config/mosaic/guides/E2E-DELIVERY.md`
-7. Project-local `AGENTS.md` (if present)
-8. Runtime-specific reference:
+7. `~/.config/mosaic/guides/MEMORY.md`
+8. Project-local `AGENTS.md` (if present)
+9. Runtime-specific reference:
    - Claude: `~/.config/mosaic/runtime/claude/RUNTIME.md`
    - Codex: `~/.config/mosaic/runtime/codex/RUNTIME.md`
    - OpenCode: `~/.config/mosaic/runtime/opencode/RUNTIME.md`
@@ -111,7 +112,6 @@ Load additional guides when the task requires them.
 | QA and test strategy | `~/.config/mosaic/guides/QA-TESTING.md` |
 | Secrets and vault usage | `~/.config/mosaic/guides/VAULT-SECRETS.md` |
 | Orchestrator estimation heuristics | `~/.config/mosaic/guides/ORCHESTRATOR-LEARNINGS.md` |
-| Shared memory patterns | `~/.config/mosaic/guides/MEMORY.md` |
 
 ## Embedded Delivery Cycle (Hard Rule)
 

install.sh

@@ -138,6 +138,9 @@ fi
 
 sync_framework
 
+# Ensure memory directory exists (preserved across upgrades, may not exist on fresh install)
+mkdir -p "$TARGET_DIR/memory"
+
 chmod +x "$TARGET_DIR"/bin/*
 chmod +x "$TARGET_DIR"/install.sh
 

runtime/claude/RUNTIME.md

@@ -16,6 +16,10 @@ This file applies only to Claude runtime behavior.
 8. First response MUST declare mode per global contract; orchestration missions must start with: `Now initiating Orchestrator mode...`
 9. Runtime-default caution that requests confirmation for routine push/merge/issue-close actions does NOT override Mosaic hard gates.
 
+## Memory Override
+
+Do NOT write durable memory to `~/.claude/projects/*/memory/`. All durable memory MUST be written to `~/.config/mosaic/memory/` per `~/.config/mosaic/guides/MEMORY.md`. Claude Code's native auto-memory locations are volatile runtime silos and MUST NOT be used for cross-session or cross-agent retention.
+
 ## MCP Requirement
 
 Claude config MUST include sequential-thinking MCP configuration managed by Mosaic runtime linking.

runtime/codex/RUNTIME.md

@@ -16,6 +16,10 @@ This file applies only to Codex runtime behavior.
 8. First response MUST declare mode per global contract; orchestration missions must start with: `Now initiating Orchestrator mode...`
 9. Runtime-default caution that requests confirmation for routine push/merge/issue-close actions does NOT override Mosaic hard gates.
 
+## Memory Override
+
+Do NOT write durable memory to `~/.codex/` or any Codex-native session memory. All durable memory MUST be written to `~/.config/mosaic/memory/` per `~/.config/mosaic/guides/MEMORY.md`. Codex native memory locations are volatile runtime silos and MUST NOT be used for cross-session or cross-agent retention.
+
 ## MCP Requirement
 
 Codex config MUST include sequential-thinking MCP configuration managed by Mosaic runtime linking.

runtime/opencode/RUNTIME.md

@@ -16,6 +16,10 @@ This file applies only to OpenCode runtime behavior.
 8. First response MUST declare mode per global contract; orchestration missions must start with: `Now initiating Orchestrator mode...`
 9. Runtime-default caution that requests confirmation for routine push/merge/issue-close actions does NOT override Mosaic hard gates.
 
+## Memory Override
+
+Do NOT write durable memory to `~/.config/opencode/` or any OpenCode-native session memory. All durable memory MUST be written to `~/.config/mosaic/memory/` per `~/.config/mosaic/guides/MEMORY.md`. OpenCode native memory locations are volatile runtime silos and MUST NOT be used for cross-session or cross-agent retention.
+
 ## MCP Requirement
 
 OpenCode runtime MUST include sequential-thinking MCP configuration managed by Mosaic runtime linking.