Migrate Phase memory ownership to Strata

[zekageri]

Summary

• bump Phase to v0.2.0 and adopt the ZekStack-standard Strata::MemoryPolicy
• route Phase graph storage, implementation ownership, callback holders, mutex storage, and task stack/TCB ownership through Strata
• replace Phase-specific PSRAM task allocation and self-deletion with an external Strata task teardown handoff
• add memory placement diagnostics, host coverage, a memory-policy example, CI ownership audits, and the Strata v0.1.1 dependency
• document the v0.1.x to v0.2.0 migration

Memory policy

• memory.allocation = Strata::Placement::Default
• memory.taskStack = Strata::Placement::PreferExternal

The task-stack default preserves the old PhaseStackType::Auto behavior.

Validation

• existing host lifecycle tests retained, including the allocation-free runtime check
• added memory-policy and diagnostics host coverage
• CI builds examples for ESP32, ESP32-S3, ESP32-C3, and ESP32-P4 with Strata v0.1.1
• source audit rejects direct allocation APIs, ESP-IDF heap-capability internals, and Phase-owned raw FreeRTOS allocation primitives