perf(test): consolidate service integration targets

[limityan]

Summary

• switch services-core and services-integrations to reviewed explicit integration-test targets
• group only tests that share the same owner, feature closure, platform, process, and failure domain
• extend the existing core-boundary checker so future leaves cannot silently narrow coverage through feature/cfg topology
• refresh the compile/dependency governance document and focused owner commands without adding CI jobs

Architecture and behavior

• no runtime code, dependency, product feature, or CI workflow changes
• session_write_lock_contracts remains an independent executable because it launches an abnormal-exit child through current_exe
• MCP Streamable HTTP remains independent from DTO/cache/vault contracts because it owns loopback TCP, SSE, timeout, and cleanup failure semantics
• Remote SSH keeps the lightweight disabled-provider contracts only when remote-ssh-concrete is absent; the exact negative gate is guarded
• 13 moved test bodies are byte-identical; only their target/module roots changed

Build evidence

Scope	Before	After	Result
services-core integration targets	20	13	tests unchanged
services-integrations integration targets	13	12	tests unchanged
selected local-storage + MCP + base SSH targets	16	8	8 fewer linked executables
local-storage EXE / PDB	25.2 / 135.7 MiB	19.2 / 91.9 MiB	fewer artifacts
base SSH EXE / PDB	3.9 / 53.5 MiB	2.8 / 43.8 MiB	fewer artifacts

Windows single-run A/B did not show a distinguishable cold-build or owner-rebuild speedup, so this PR does not claim compile-time improvement. It does reduce link targets and artifacts. Module filters reduce executed tests, not compilation/linking of the grouped target, and grouping intentionally trades some process-level isolation only within the same failure domain.

Validation

• pnpm run check:core-boundaries:test — 69/69
• pnpm run check:core-boundaries
• services-core grouped local-storage targets — 58/58
• MCP targets kept independent — 43/43 + 2/2
• Remote SSH target — 11/11 with base feature, 9/9 with concrete provider
• changed Rust files pass rustfmt --check
• git diff --check gcwing/main...HEAD
• rebased on gcwing/main@c6badb778

Cross-platform and packaging matrices remain with the existing CI; no duplicate test job was added.

AI-assisted: yes. Testing level: fully tested for the changed Windows owner scope; cross-platform CI pending.