refactor(tools): close H1 manifest catalog baseline

[limityan]

Summary

• Close the H1 tool manifest/catalog baseline as one PR-sized milestone instead of a small helper-only slice.
• Move pure prompt-visible manifest, manifest-policy input, generic collapsed exposure query, and GetToolSpec catalog-description helpers into bitfun-agent-tools.
• Keep core as the runtime owner by delegating only pure helper assembly from manifest_resolver, ToolRegistry, and GetToolSpecTool.
• Update boundary checks and decomposition docs so future work does not mistake pure helper extraction for runtime owner migration.

Functional Boundary

• No concrete tool implementation moved.
• No ToolUseContext, workspace services, cancellation token, computer-use host, snapshot decorator, runtime unlock state, or GetToolSpec execution moved out of core.
• No Cargo dependency, feature, CLI, desktop, ACP, MCP, or remote surface behavior changes.
• Product collapsed-tool catalog and context-aware schema/description resolution remain core-owned.

Review Notes

• Added agent-tools contract tests for generic exposure catalog queries, manifest policy input preservation, prompt-visible definitions, and GetToolSpec catalog copy.
• Strengthened scripts/check-core-boundaries.mjs anchors so agent-tools can own only pure helper contracts while core still owns runtime assembly and execution anchors.
• Rechecked docs against the latest upstream main after rebase; updated both the architecture guardrail and implementation plan to distinguish generic exposure helper ownership from product runtime catalog ownership.

Verification

• rustfmt --edition 2024 --check src/crates/agent-tools/src/framework.rs src/crates/agent-tools/src/lib.rs src/crates/agent-tools/tests/tool_contracts.rs src/crates/core/src/agentic/tools/implementations/get_tool_spec_tool.rs src/crates/core/src/agentic/tools/manifest_resolver.rs src/crates/core/src/agentic/tools/registry.rs
• node scripts/check-core-boundaries.mjs
• cargo test -p bitfun-agent-tools
• cargo test -p bitfun-core registry_ --lib
• cargo test -p bitfun-core manifest_ --lib
• cargo test -p bitfun-core get_tool_spec --lib
• cargo test -p bitfun-core pipeline_preserves_core_owned_tool_context_without_portable_runtime_leak --lib
• cargo check --workspace
• cargo test --workspace
• git diff --check