feat(agentic-circuit): emit per-module ACIR and gfsim units

[zhoubot]

Summary

• emit sorted modules/<symbol>.ac.mlir inspection units alongside whole-program Frozen ACIR
• emit one nominal type header, one declaration/out-of-line implementation pair per concrete gfsim module specialization, a helper implementation TU, and root composition/runtime glue
• compile every generated C++ source as a separate object and link the complete object set
• bind model plan, emit, CMake, depfile, and manifest to one exact deterministic inventory; preserve mtimes for byte-identical repeat emit
• preserve non-zero scalar reset images, including the full unsigned 64-bit pattern, and keep source/JIT specialization distinct from structural QueueGraph specialization

pyc6 Decision / Contract Impact

• Decision ID: 0264
• Extends Decisions 0169, 0170, 0178, 0179, 0258, 0260, and 0263
• Frozen ACIR remains the verified whole-program semantic authority
• Per-module ACIR files are inspection units, not independently linkable ACIR modules

Validation

• CodeGenTests: 172/172 passed
• CompilerTests: 11/11 passed
• focused Agentic lit: 5/5 passed
• Agentic frontend: 239/239 passed
• root unit suite: 147/147 passed
• focused model plan/emit: 5/5 passed
• contract checker, diagnostic catalog, API hygiene, strict MkDocs, changed-file pre-commit, formatting, and strict decision status passed
• generated module/helper/root/model sources compile independently with -c, link with gfsim, and execute the reused stateful model successfully

Evidence

• docs/gates/logs/20260916-per-module-acir-multitu/summary.md
• docs/gates/logs/20260916-per-module-acir-multitu/commands.txt

Known Baseline

The checkout-wide ACIROpsTests run passes 1840/1842. Its two failures are the pre-existing exact operation-registry inventory/count baseline: 152 registered operations versus the stale expected 151.

Follow-up Boundary

Independent ACIR compilation still needs a verified module signature/import/link contract. This PR deliberately does not bypass whole-program freeze or claim that per-module dumps are standalone link inputs.