feat(search): path_excludes filter + teach the MCP keyword-OR / noise-dir exclusion

[githubrobbi]

Why

An LLM was asked "find my solar/energy spreadsheets" and (a) hallucinated CLI flags, (b) ran 8 separate searches (one per keyword), and (c) claimed "UFFS MCP doesn't have path-exclude." Two real causes:

1. Teaching gap — regex-OR and the existing filters (exclude, match_path) weren't in the agent instructions.
2. Capability gap — exclude matches the filename, path_contains is a positive include, so there was genuinely no way to drop noise directories (.cargo, AppData, …). The agent was right.

What this does

Capability — new path_excludes

A comma-separated list of directory-path globs; a record is dropped when its directory matches any entry (inverse of path_contains, multi-value so several noise dirs go in one query). Wired end-to-end:
SearchParams (protocol) → SearchFilters (core; parsing in path_normalize::parse_path_excludes — comma-split, lowered, separator-normalized) → daemon → MCP uffs_search tool → --not-in-path CLI flag mirroring --in-path.

Teaching — AGENT_INSTRUCTIONS

• KEYWORD-OR with ONE regex >(a|b|c) (case-insensitive), never N searches;
• path_excludes (noise dirs), exclude (filename glob), match_path;
• documents collection covers xls/xlsx;
• a worked "topic files in a folder, minus dev noise" one-call example.

So the failure becomes:

uffs_search pattern='>(solar|energy|utility|pge|sunrun)' ext='xls,xlsx' \
  path_contains='Users\\name' path_excludes='*appdata*,*.cargo*,*.rustup*'

Tests / verification

from_params_path_excludes_* (comma-split / lowercase / normalize / None-on-blank). macOS + x86_64-pc-windows-msvc builds + clippy clean; full pre-push gate green. filters/mod.rs (cohesive struct + from_params) registered in file_size_exceptions.txt as it crosses the 800-LOC line.

🤖 Generated with Claude Code