Fixes #1617.

Summary

• include generic tool input in approval-cache fingerprints
• keep identical generic tool requests stable so exact repeat denials still auto-deny
• prevent one denied edit_file/generic approval from blocking every future request of that tool type

Verification

• RED: cargo test -p deepseek-tui --bin deepseek-tui --locked generic_tool
• cargo fmt --all -- --check
• cargo test -p deepseek-tui --bin deepseek-tui --locked generic_tool - 10 tests passed
• cargo test -p deepseek-tui --bin deepseek-tui --locked approval_cache - 10 tests passed
• cargo clippy -p deepseek-tui --all-targets --all-features --locked -- -D warnings
• git diff --check

Release Safety

• Review PR only.
• No merge, tag, publish, force-push, or issue closure performed.