feat: standalone file search CLI (#1386)

Standalone fuzzy filename search library that should be helpful in
addressing https://github.com/openai/codex/issues/1261.

codex-rs/Cargo.lock

@@ -691,6 +691,18 @@ dependencies = [
  "tempfile",
 ]
 
+[[package]]
+name = "codex-file-search"
+version = "0.0.0"
+dependencies = [
+ "anyhow",
+ "clap",
+ "ignore",
+ "nucleo-matcher",
+ "serde_json",
+ "tokio",
+]
+
 [[package]]
 name = "codex-linux-sandbox"
 version = "0.0.0"
@@ -1601,6 +1613,19 @@ version = "0.3.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "a8d1add55171497b4705a648c6b583acafb01d58050a51727785f0b2c8e0a2b2"
 
+[[package]]
+name = "globset"
+version = "0.4.16"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "54a1028dfc5f5df5da8a56a73e6c153c9a9708ec57232470703592a3f18e49f5"
+dependencies = [
+ "aho-corasick",
+ "bstr",
+ "log",
+ "regex-automata 0.4.9",
+ "regex-syntax 0.8.5",
+]
+
 [[package]]
 name = "h2"
 version = "0.4.9"
@@ -1985,6 +2010,22 @@ dependencies = [
  "icu_properties",
 ]
 
+[[package]]
+name = "ignore"
+version = "0.4.23"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6d89fd380afde86567dfba715db065673989d6253f42b88179abd3eae47bda4b"
+dependencies = [
+ "crossbeam-deque",
+ "globset",
+ "log",
+ "memchr",
+ "regex-automata 0.4.9",
+ "same-file",
+ "walkdir",
+ "winapi-util",
+]
+
 [[package]]
 name = "image"
 version = "0.25.6"
@@ -2577,6 +2618,16 @@ dependencies = [
  "winapi",
 ]
 
+[[package]]
+name = "nucleo-matcher"
+version = "0.3.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bf33f538733d1a5a3494b836ba913207f14d9d4a1d3cd67030c5061bdd2cac85"
+dependencies = [
+ "memchr",
+ "unicode-segmentation",
+]
+
 [[package]]
 name = "num-bigint"
 version = "0.4.6"
@@ -4362,6 +4413,7 @@ dependencies = [
  "bytes",
  "libc",
  "mio",
+ "parking_lot",
  "pin-project-lite",
  "signal-hook-registry",
  "socket2",