Phase 26: Adaptive Runtime Agent & Hybrid Execution

[t81dev]

This PR implements Phase 26 of the TFMBS roadmap: the Adaptive Runtime Agent and Hybrid Execution paths.

Key features:

1. Adaptive Decision Engine: Located in src/libtfmbs_device.c, the agent monitors kernel sparsity in real-time using an EMA and decides whether to offload to the Ternary Fabric or fallback to the host CPU.
2. Hysteresis & Recovery: To avoid being "stuck" in a CPU-fallback state when sparsity drops temporarily, the agent implements a periodic probe mechanism that forces a Fabric execution every $N$ kernels to re-evaluate performance.
3. Realistic Driver API: Pre-emptively matured the Mock Driver (Phase 22 prep) by adding IOCTLs for residency querying and memory pinning, aligning the software stack with the upcoming physical hardware requirements.
4. Telemetry & Benchmarking: Added new metrics for tracking offload/fallback ratios and included a dedicated stress test (test_adaptive.c) to verify the switching logic.

Configuration is handled via environment variables:

• TFMBS_ADAPTIVE_POLICY: offload, fallback, or sparsity.
• TFMBS_SPARSITY_THRESHOLD: Float value (default 0.3).
• TFMBS_EMA_ALPHA: Smoothing factor for sparsity tracking.

Verified with test_adaptive and existing test_device suites.

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PR created automatically by Jules for task 8366195443512061802 started by @t81dev

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