fix(embed): preserve profile HINDSIGHT guardrails

[grabyourfiles]

Summary

• load and merge profile .env before daemon already-running short-circuits
• preserve all HINDSIGHT_* keys during profile registration, including HINDSIGHT_EMBED_* daemon guardrails
• add regression coverage for HINDSIGHT_EMBED_DAEMON_IDLE_TIMEOUT and consolidation env preservation
• avoid cross-platform ty false positives for Windows-only subprocess constants

Why

hindsight-embed -p <profile> daemon start can re-register profile metadata even when a daemon is already running. Passing only the caller-provided config to registration can silently erase persisted profile guardrails such as HINDSIGHT_EMBED_DAEMON_IDLE_TIMEOUT=0 or consolidation token limits.

Test plan

• cd hindsight-embed && uv run ruff check hindsight_embed/daemon_embed_manager.py tests/test_profile_daemon_config.py
• cd hindsight-embed && uv run pytest tests/test_profile_daemon_config.py -q
• cd hindsight-embed && uv run pytest tests -q
• cd hindsight-embed && uv run ty check hindsight_embed/daemon_embed_manager.py tests/test_profile_daemon_config.py