IR-496: Generate bounded flat function schedules

[kreneskyp]

Summary

• Generate deterministic flat SSA schedules for strictly admitted function call graphs with explicit enter/finish traversal, typed values, and parent-linked source locations.
• Preserve exact declaration identity and argument binding; refuse cycles, shared call nodes, malformed bindings, and resource-limit violations before publishing a partial schedule.
• Charge work before each schedule action, with exact-limit and one-less controls, and partition large generated schedules into deterministic modules under the source ceiling.
• Exercise the public strict-reader path with a 100,000-call chain on a 512 KiB worker stack, including generated-crate compilation and source-limit controls.

Refs IR-496. This scoped slice does not claim the QSL-owned FR-021-AC-18 agreement leg.

Evidence

• Pre-push wrapper on a7f25276dbc40fda8efb1ca50e44bc9b4c873903: fmt, clippy, cargo check, and focused acceptance tests passed. The repository has no string-edge/xtask endpoint; this was recorded as unavailable.
• First pre-PR make -k ci on the same head passed. Unit tests: 232/232; integration tests: 492 passed, 27 ignored; doctest: 1/1. The 100K AC-7 schedule test passed in both full test passes.
• Formal make kani-gate passed 27/27 on the same clean head (Kani 0.68.0, CBMC 6.11.0).
• Independent code/Rust review SR-8640: PASS, no new findings. Changed-scope gap analysis SR-8641: PASS for the reviewed FR-021 schedule criteria; the repository-wide matrix retains unrelated untagged criteria.

Full gate log: /tmp/ir496-prepr-make-k-ci-a7f2527.log
Kani log: /tmp/ir496-kani-gate-a7f2527.log