refactor(tools): TypedTool trait + input/schema normalization

[yishuiliunian]

Summary

• Introduce TypedTool<P> trait + TypedBridge adapter for compile-time schema-parameter safety — eliminates hand-written JSON schemas and manual Value parsing across all 23 builtin tools
• Split Bash tool into Bash (command execution) + BashProcess (process management) to eliminate flag argument anti-pattern
• Add input normalization (empty string → None for optional fields) and schema normalization ($ref inlining, $schema/title removal) in TypedBridge

Changes

• crates/loopal-tool-api/src/ — new: typed_tool.rs, typed_bridge.rs, input_normalize.rs, schema_normalize.rs
• crates/tools/process/bash-process/ — new crate for BashProcessTool
• crates/tools/process/background/src/ops.rs — migrated from bash/bg_ops.rs
• All 23 tool crates migrated from impl Tool to impl TypedTool<XxxParams>
• All tool BUILD.bazel files updated with schemars dep
• Registry builtin/mod.rs updated to use TypedBridge registration

Test plan

• 74/74 bazel tests pass
• clippy clean (zero warnings)
• rustfmt clean
• Integration tests verify empty string → None E2E through TypedBridge
• Integration tests verify schema output has no $schema/$ref/title