Migrate Trace memory ownership to Strata

[zekageri]

Summary

Migrate Trace from its library-specific heap/task/mutex policy to the shared ZekStack Strata model and prepare the v0.3.0 release.

Memory policy

• Pin Strata v0.1.2.
• Replace TraceStackType and TraceStorageMemory with Strata::MemoryPolicy, Strata::Placement, and Strata::Region.
• Prefer external memory by default for all movable Trace-owned allocations and for the Trace task stack.
• Keep realtimeAllocation as an optional override; std::nullopt inherits memory.allocation.
• Keep the small Trace root/control object and RTOS control storage internal; they are intentionally outside the movable payload policy.
• Re-home callback holders registered before init() after the requested runtime policy is applied, so callback ownership follows memory.allocation / realtimeAllocation.

Ownership

• Replace the direct ESP heap-cap allocator with Strata::Buffer while preserving the fixed TraceRecord ring-buffer design.
• Replace the dynamically-created recursive mutex with Strata::FreeRTOS::RecursiveMutex.
• Replace Trace's task-support shim with Strata::FreeRTOS::Task.
• Change task shutdown from self-deletion to an external publish/suspend/reset handoff so Strata-owned static task storage is always freed from another task context.
• Preserve ownership after a timed end() and make the destructor perform final cleanup.
• Repeated end() calls during shutdown no longer restart or extend the original shutdown deadline; a later call can safely reap the task after a previously reported timeout.
• Allocate callback holders through Strata.

Public/output allocations

• Change TraceResult::message to const char * because Trace result messages are static literals.
• Back TraceLog strings with Strata::String.
• Add TraceLogList = Strata::Vector<TraceLog> and use it for query results and flush batches.
• Build formatted strings through their Strata allocator rather than temporary default-allocator strings.
• Keep the fixed direct C-string enqueue path allocation-free after initialization.

Diagnostics

Replace Trace-specific PSRAM booleans/stack enums with requested placement and observed region diagnostics for general allocation, realtime allocation, task stack, and all three ring buffers.

Validation and docs

• Add Strata v0.1.2 to PlatformIO/Arduino/host CI.
• Add source audits preventing direct heap-cap allocation and direct dynamic FreeRTOS ownership from returning to Trace.
• Keep a Strata-specific host suite covering placement propagation, required-external failures, static-task ownership, repeated init/end, timed shutdown cleanup, destructor cleanup, and the zero-allocation C-string hot path.
• Restore the v0.2.1 behavioral regression coverage as a second host binary, including realtime behavior/overflow, all pending overflow policies, retry/backoff semantics, callback locking, truncation, shutdown outcomes, capped flush barriers, and sequence ordering.
• Update examples/docs and add a MemoryPolicy example.
• Document the control-state vs movable-payload ownership boundary and pre-init callback re-homing behavior.
• Bump library metadata from v0.2.1 to v0.3.0.

v0.2.x migration

v0.2.x	v0.3.0
TraceStackType::Auto	Strata::Placement::PreferExternal
TraceStackType::Internal	Strata::Placement::Internal
TraceStackType::Psram	Strata::Placement::RequireExternal
TraceStorageMemory::Internal	Strata::Placement::Internal
TraceStorageMemory::PreferPsram	Strata::Placement::PreferExternal
TraceStorageMemory::RequirePsram	Strata::Placement::RequireExternal
config.stackType	config.memory.taskStack
config.storageMemory	config.memory.allocation
config.realtimeStorageMemory	config.realtimeAllocation
std::vector<TraceLog> query results	TraceLogList
TraceResult::message (std::string)	const char *

The v0.3.0 default is intentionally PSRAM-first: memory.allocation and memory.taskStack are both PreferExternal, and realtime allocations inherit the general policy unless explicitly overridden.