Format large numbers in a more readable way. (#2046)

- In the bottom line of the TUI, print the number of tokens to 3 sigfigs
  with an SI suffix, e.g. "1.23K".
- Elsewhere where we print a number, I figure it's worthwhile to print
  the exact number, because e.g. it's a summary of your session. Here we print
  the numbers comma-separated.

codex-rs/Cargo.lock

@@ -917,6 +917,8 @@ name = "codex-protocol"
 version = "0.0.0"
 dependencies = [
  "base64 0.22.1",
+ "icu_decimal",
+ "icu_locale_core",
  "mcp-types",
  "mime_guess",
  "pretty_assertions",
@@ -926,6 +928,7 @@ dependencies = [
  "serde_with",
  "strum 0.27.2",
  "strum_macros 0.27.2",
+ "sys-locale",
  "tracing",
  "ts-rs",
  "uuid",
@@ -1758,6 +1761,17 @@ dependencies = [
  "winapi",
 ]
 
+[[package]]
+name = "fixed_decimal"
+version = "0.7.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "35943d22b2f19c0cb198ecf915910a8158e94541c89dcc63300d7799d46c2c5e"
+dependencies = [
+ "displaydoc",
+ "smallvec",
+ "writeable",
+]
+
 [[package]]
 name = "fixedbitset"
 version = "0.4.2"
@@ -2257,6 +2271,45 @@ dependencies = [
  "zerovec",
 ]
 
+[[package]]
+name = "icu_decimal"
+version = "2.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "fec61c43fdc4e368a9f450272833123a8ef0d7083a44597660ce94d791b8a2e2"
+dependencies = [
+ "displaydoc",
+ "fixed_decimal",
+ "icu_decimal_data",
+ "icu_locale",
+ "icu_locale_core",
+ "icu_provider",
+ "tinystr",
+ "writeable",
+ "zerovec",
+]
+
+[[package]]
+name = "icu_decimal_data"
+version = "2.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b70963bc35f9bdf1bc66a5c1f458f4991c1dc71760e00fa06016b2c76b2738d5"
+
+[[package]]
+name = "icu_locale"
+version = "2.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6ae5921528335e91da1b6c695dbf1ec37df5ac13faa3f91e5640be93aa2fbefd"
+dependencies = [
+ "displaydoc",
+ "icu_collections",
+ "icu_locale_core",
+ "icu_locale_data",
+ "icu_provider",
+ "potential_utf",
+ "tinystr",
+ "zerovec",
+]
+
 [[package]]
 name = "icu_locale_core"
 version = "2.0.0"
@@ -2270,6 +2323,12 @@ dependencies = [
  "zerovec",
 ]
 
+[[package]]
+name = "icu_locale_data"
+version = "2.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4fdef0c124749d06a743c69e938350816554eb63ac979166590e2b4ee4252765"
+
 [[package]]
 name = "icu_normalizer"
 version = "2.0.0"
@@ -3514,6 +3573,7 @@ version = "0.1.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e5a7c30837279ca13e7c867e9e40053bc68740f988cb07f7ca6df43cc734b585"
 dependencies = [
+ "serde",
  "zerovec",
 ]
 
@@ -4850,6 +4910,15 @@ dependencies = [
  "yaml-rust",
 ]
 
+[[package]]
+name = "sys-locale"
+version = "0.3.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8eab9a99a024a169fe8a903cf9d4a3b3601109bcc13bd9e3c6fff259138626c4"
+dependencies = [
+ "libc",
+]
+
 [[package]]
 name = "system-configuration"
 version = "0.6.1"