Fix SCHEMATIC nested-loop energy accounting and estimator FRAM costs

[byeongjee]

Summary

Energy-model corrections for SCHEMATIC's nested-loop accounting and the
assembly estimator's FRAM stack costs, plus a new pass that repairs trip-count
metadata the compiler duplicates when it splits an annotated loop.

SCHEMATIC loop energy

• Charge nested loop iterations in the shared energy propagation, and charge the
  restore cost in the loop iteration budget.
• Replace a hand-inlined second copy of both propagation walkers in
  recomputeLoopBodyEnergyOnCFG (~230 lines) with calls to the shared ones. The
  inline copy had already drifted: it skipped only the analyzed loop's own back
  edge, while the shared walker skips every back edge it reaches.
• Convert estimator block costs to SCHEMATIC's all-NVM convention.

Assembly estimator / FRAM stack

• Charge FRAM stack accesses (--stack-access-penalty) for the pipelines whose
  linker script places the stack in FRAM (SCHEMATIC, RockClimb), counting only
  memory-accessing stack operands.
• Charge the same in RockClimb's machine-level energy pass.

Trip-count metadata

• UnifyAnnotatedLoopPass merges a loop pair that LoopSimplify split apart.
  Loop::setLoopID stamps the annotation on every latch of a multi-latch loop,
  so after separateNestedLoop both halves claim the full trip count. Verified
  on rsa: the latches of while.cond.i and while.cond.i.outer both carry
  !llvm.loop !21 = tripcount.upper 96, so a consumer that multiplies sees
  9216 instead of 96.

MILP liveness

• Treat promoted allocas as dead at entry, scoped to main — the only function
  AllocaToGlobalPass transforms.

Robustness fixes from review

• SCHEMATIC now fails loudly when a loop body still does not fit after being
  split: splitLoopBodyAtFixedBoundary reports whether every body path got a
  boundary (a path with no fixed boundary is infeasible, not ignorable), the
  budget is re-checked after the split-and-recompute, and the decision.final*
  diagnostics are recorded after the budget settles rather than before.
• push/pop/call now also charge their operand's access, so
  push 4(r1) counts two FRAM accesses rather than one.
• UnifyAnnotatedLoopPass initializes logging like every other pass; without it
  its only diagnostic was dropped whenever it ran first.
• The RockClimb preprocess test configs declare nvm_access_penalty. The
  compile path genuinely requires it, so the loader still fails loudly on a real
  config that omits it.

Test plan

• uv run pytest tests/ — 257 passed.
• Results are being re-measured; results/milp_debug.csv had mixed provenance
  (a full run at 8c8c013 with only the three rsa rows overwritten from a later
  rsa-only rerun) and is being regenerated in full.