refactor(core): extract path_resolver module, fix old_path matching in who

Extract shared path resolution logic from who.rs into a new
core::path_resolver module for cross-module reuse. Functions moved:
escape_like, normalize_repo_path, PathQuery, SuffixResult,
build_path_query, suffix_probe. Duplicate escape_like copies removed
from list.rs, project.rs, and filters.rs — all now import from
path_resolver.

Additionally fixes two bugs in query_expert_details() and
query_overlap() where only position_new_path was checked (missing
old_path matches for renamed files) and state filter excluded 'closed'
MRs despite the main scoring query including them with a decay
multiplier.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/core/project.rs

@@ -1,6 +1,7 @@
 use rusqlite::Connection;
 
 use super::error::{LoreError, Result};
+use super::path_resolver::escape_like;
 
 pub fn resolve_project(conn: &Connection, project_str: &str) -> Result<i64> {
     let exact = conn.query_row(
@@ -106,13 +107,6 @@ pub fn resolve_project(conn: &Connection, project_str: &str) -> Result<i64> {
 
 /// Escape LIKE metacharacters so `%` and `_` in user input are treated as
 /// literals.  All queries using this must include `ESCAPE '\'`.
-fn escape_like(input: &str) -> String {
-    input
-        .replace('\\', "\\\\")
-        .replace('%', "\\%")
-        .replace('_', "\\_")
-}
-
 #[cfg(test)]
 #[path = "project_tests.rs"]
 mod tests;