What does this PR do?

Adds backwards-compatible write-origin metadata to external memory provider mirrors for built-in memory writes. Providers that opt into the new metadata argument can distinguish foreground assistant memory-tool writes from background review writes and memory-flush writes without parsing memory text.

The manager still supports existing third-party providers that implement the old 3-argument on_memory_write(action, target, content) hook.

Related Issue

Fixes #15219

Type of Change

• 🐛 Bug fix (non-breaking change that fixes an issue)
• ✨ New feature (non-breaking change that adds functionality)
• 🔒 Security fix
• 📝 Documentation update
• ✅ Tests (adding or improving test coverage)
• ♻️ Refactor (no behavior change)
• 🎯 New skill (bundled or hub)

Changes Made

• agent/memory_provider.py: adds optional metadata to MemoryProvider.on_memory_write(...).
• agent/memory_manager.py: forwards metadata to opt-in providers while preserving old 3-arg provider compatibility.
• run_agent.py: builds write provenance metadata for foreground memory tools, background review agents, and memory flush writes.
• plugins/memory/*: updates bundled provider hook signatures; Supermemory includes the provenance in its memory metadata.
• tests/agent/test_memory_provider.py and tests/run_agent/test_flush_memories_codex.py: cover opt-in metadata delivery, legacy compatibility, and flush provenance.

How to Test

1. Targeted: ./scripts/run_tests.sh tests/agent/test_memory_provider.py tests/run_agent/test_flush_memories_codex.py tests/plugins/memory/test_supermemory_provider.py tests/plugins/test_retaindb_plugin.py -n 4
2. Result: 166 passed in 7.35s.
3. Full suite: ./scripts/run_tests.sh tests/ -n 4
4. Result: 54 failed, 15434 passed, 40 skipped, 185 warnings in 306.60s. The failures are broad pre-existing repo/environment failures in gateway, Dingtalk, Codex response, backup/profile wrapper, and Tirith tests, not in the targeted memory-provider coverage.

Checklist

Code

• I have read the Contributing Guide
• My commit messages follow Conventional Commits
• I searched for existing PRs to make sure this is not a duplicate
• My PR contains only changes related to this fix/feature
• I have run pytest tests/ -q and all tests pass
• I have added tests for my changes
• I have tested on my platform: Ubuntu/WSL2-style Linux workspace

Documentation & Housekeeping

• I have updated relevant documentation/docstrings, or N/A
• I have updated cli-config.yaml.example if I added/changed config keys, or N/A
• I have updated CONTRIBUTING.md or AGENTS.md if I changed architecture or workflows, or N/A
• I have considered cross-platform impact, or N/A
• I have updated tool descriptions/schemas if I changed tool behavior, or N/A

Screenshots / Logs

Targeted memory-provider tests pass. Full suite currently has unrelated baseline failures listed above.