perf(test): isolate runtime test support and consolidate CLI contracts

[limityan]

Summary

• Keep bitfun-runtime-services::test_support out of ordinary library builds and enable it only for owner tests or explicit dev-dependency consumers.
• Preserve the runtime-services owner contract suite in the default crate test target, so cargo test -p bitfun-runtime-services still runs all 11 tests.
• Consolidate four related CLI command/product contract targets into one cli_command_contracts target while keeping ACP and terminal process contracts independent.
• Extend the existing core-boundary checker to lock the three-target CLI topology, grouped leaf ownership, and dev-only test-support feature edges.

No GitHub Actions workflow was added or changed.

Architecture

• Runtime fakes remain owned by Execution and do not enter normal/build dependency graphs.
• Assembly and Agent Runtime consume the fake only through dev-dependencies; SDK smoke tests keep their narrower public-SDK fake.
• CLI target consolidation changes test assembly only. Product behavior, command ownership, runtime wiring, and production features are unchanged.
• The topology guard intentionally checks Cargo targets, top-level roots, and grouped leaf ownership only; a proposed source-level Rust macro parser was removed during review as disproportionate governance.

Build impact

Measurements used the same Windows worktree and dependency cache, warmed each feature fingerprint, cleaned only bitfun-cli, and forced -j 1 because other workspace builds were active on the host.

Scenario	Before	After	Change
Full CLI test --no-run	141.002 s	139.474 s	-1.1%
Related artifact files	18	9	-50.0%
Related artifact bytes	44,293,955	30,466,416	-31.2%
Focused plugin contract recompile	1.507 s	1.664 s	+0.157 s

The wall-time result is intentionally reported as near-neutral rather than a large speedup; the material win is reduced duplicate test artifacts without losing focused test filters.

Validation

• pnpm run fmt:rs
• pnpm run check:core-boundaries:test — 44/44
• pnpm run check:core-boundaries
• cargo check --workspace --exclude bitfun-desktop --locked
• cargo test -p bitfun-runtime-services --locked — 11/11
• cargo test -p bitfun-product-capabilities --locked — 30/30
• cargo test -p bitfun-cli --locked --test acp_stdio_cli --test cli_command_contracts --test terminal_process_contracts — 41/41
• cargo test -p bitfun-agent-runtime --tests --locked
• cargo test -p bitfun-core --features product-full --lib --locked — 1814 passed, 1 ignored

A full cargo check --workspace --locked reached the desktop build script and stopped because this isolated worktree does not contain generated src/mobile-web/dist. The same check excluding bitfun-desktop passed; no generated frontend output was created or committed.

Two independent adversarial reviewers examined the feature graph, layer direction, Cargo test discovery, path equivalence, focused-test behavior, and checker scope over multiple rounds. The final reduced design has no outstanding P1/P2 finding.