[FLO-13.2b] Exercise bounded provider lifecycle and protocol outcomes

[szmyty]

Parent: #29
Depends on #47 (merged as 9ac6a7a47e0544c0711fe7ad9caab32dd6720ca8)
Closes #45
Next checkpoint: #46

Summary

• extend the immutable hermetic provider fixture with a closed lifecycle/protocol behavior vocabulary
• cover unavailable/incompatible prelaunch resolution, warning and partial results, nonzero exit, timeout/cancellation, both stream overflows, invalid event/result evidence, and authoritative host rejection
• preserve the checkpoint-1 success path while documenting exact ownership boundaries and typed outcomes

Evidence

• exact typed errors and promotion boundaries are asserted for every case
• stdout/stderr retention is bounded to the configured limit plus one sentinel byte
• cancellation uses an atomically published readiness record; timeout and cancellation prove direct-child reaping on Unix
• all invoked lifecycle cases pin forbidden fallback, re-observe execution subjects, and preserve immutable input/binding bytes
• two independent post-implementation reviews found no remaining blocker

Validation

• Rust 1.85: formatting, clippy with warnings denied, all targets, doc tests, focused provider/kit tests
• stable Rust: formatting, clippy with warnings denied, all targets, doc tests
• all three runnable examples
• cargo package --locked --allow-dirty
• contract, scenario-source, specification, skill, and agent validators
• git diff --check

Scope boundary

This checkpoint does not add physical artifact adversaries, post-success host artifact-observation cases, graph fixtures, real holon algorithms, sandbox or descendant-containment claims, durable retry/resume, or the final parent requirement matrix. Those remain with #46 or later work.

Integration status

Retargeted to main after #47 merged. Head 028deddbc26c0f8d228fe2d2dbb87b8d18887049 integrates current main without changing the checkpoint implementation. Fresh CI run 35854026666 passed repository validators, Rust 1.85, stable Rust, tests, documentation, examples, and package verification.