feat(pyc): add qualified semantic primitive pipeline

[zhoubot]

Summary

• add vendor-neutral pyc.priority_encode and simple structural/Cycle-Aware Python APIs
• keep C++ on reference semantics while a Verilog-only pass selects internal pyc.rtl.comb
• add a validated BSD-3-Clause RTL catalog, digest verification, fail-closed raw-binding rejection, explicit selection priority, minimal source bundling, and versioned manifest definitions/bindings
• preserve selected RTL closure across multi-module Python builds
• add ac.priority_encode(...).index/.valid, ACIR verification, shared QueueGraph lowering, gfsim PriorityEncode SimQueue block, and ACIR-to-PYC-to-selected-RTL coverage
• record Decision 0161 and keep stateful/handshake/CDC PR feat(runtime): integrate Verilog crawler and catalog #29 candidates blocked on the inferred prepare/publish/no-fail commit contract

Dependency

• stacked on PR feat(agentic): add exact u1-u64 bit types #32 (ac.u1 through ac.u64); retarget to main after feat(agentic): add exact u1-u64 bit types #32 merges

Validation

• root unit + primitive system: 23 passed
• Agentic frontend/direct codegen: 74 passed
• ACIR/ACSim lit: 139/139
• AC CTest: 15/15
• PYC selector raw-binding, digest, ambiguity, width, and verifier failures: passed
• PYC C++ reference and selected Verilog/Verilator/Icarus parity: passed
• Agentic ACPy -> Frozen ACIR -> QueueGraph -> gfsim C++ compile: passed
• Agentic ACPy -> Frozen ACIR -> PYC -> selected RTL Verilator: passed
• contracts, IR coverage, strict decision status (161 rows), API hygiene, bash syntax, and MkDocs strict: passed

Evidence

• docs/gates/logs/20260905-pyc-priority-rtl-r1/summary.md

Scope boundary

• This PR admits the first pure combinational family only. It does not claim Issue [ACIR/ACPy] firing问题讨论 #28's stateful cross-resource atomic commit work is complete.