Replace bespoke CLI line editing with rustyline and canonical model aliases

The REPL now wraps rustyline::Editor instead of maintaining a custom raw-mode
input stack. This preserves the existing LineEditor surface while delegating
history, completion, and interactive editing to a maintained library. The CLI
argument parser and /model command path also normalize shorthand model names to
our current canonical Anthropic identifiers.

Constraint: User requested rustyline 15 specifically for the CLI editor rewrite
Constraint: Existing LineEditor constructor and read_line API had to remain stable
Rejected: Keep extending the crossterm-based editor | custom key handling and history logic were redundant with rustyline
Rejected: Resolve aliases only for --model flags | /model would still diverge from CLI startup behavior
Confidence: high
Scope-risk: moderate
Reversibility: clean
Directive: Keep model alias normalization centralized in main.rs so CLI flag parsing and /model stay in sync
Tested: cargo check --workspace
Tested: cargo test --workspace
Tested: cargo build --workspace
Tested: cargo clippy --workspace --all-targets -- -D warnings
Not-tested: Interactive manual terminal validation of Shift+Enter behavior across terminal emulators

rust/Cargo.lock

@@ -98,6 +98,15 @@ version = "0.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "613afe47fcd5fac7ccf1db93babcb082c5994d996f20b8b159f2ad1658eb5724"
 
+[[package]]
+name = "clipboard-win"
+version = "5.4.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bde03770d3df201d4fb868f2c9c59e66a3e4e2bd06692a0fe701e7103c7e84d4"
+dependencies = [
+ "error-code",
+]
+
 [[package]]
 name = "commands"
 version = "0.1.0"
@@ -142,7 +151,7 @@ dependencies = [
  "crossterm_winapi",
  "mio",
  "parking_lot",
- "rustix",
+ "rustix 0.38.44",
  "signal-hook",
  "signal-hook-mio",
  "winapi",
@@ -197,6 +206,12 @@ dependencies = [
  "syn",
 ]
 
+[[package]]
+name = "endian-type"
+version = "0.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c34f04666d835ff5d62e058c3995147c06f42fe86ff053337632bca83e42702d"
+
 [[package]]
 name = "equivalent"
 version = "1.0.2"
@@ -213,6 +228,23 @@ dependencies = [
  "windows-sys 0.61.2",
 ]
 
+[[package]]
+name = "error-code"
+version = "3.3.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "dea2df4cf52843e0452895c455a1a2cfbb842a1e7329671acf418fdc53ed4c59"
+
+[[package]]
+name = "fd-lock"
+version = "4.0.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0ce92ff622d6dadf7349484f42c93271a0d49b7cc4d466a936405bacbe10aa78"
+dependencies = [
+ "cfg-if",
+ "rustix 1.1.4",
+ "windows-sys 0.52.0",
+]
+
 [[package]]
 name = "find-msvc-tools"
 version = "0.1.9"
@@ -351,6 +383,15 @@ version = "0.16.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "841d1cc9bed7f9236f321df977030373f4a4163ae1a7dbfe1a51a2c1a51d9100"
 
+[[package]]
+name = "home"
+version = "0.5.12"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cc627f471c528ff0c4a49e1d5e60450c8f6461dd6d10ba9dcd3a61d3dff7728d"
+dependencies = [
+ "windows-sys 0.61.2",
+]
+
 [[package]]
 name = "http"
 version = "1.4.0"
@@ -614,6 +655,12 @@ version = "0.4.15"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d26c52dbd32dccf2d10cac7725f8eae5296885fb5703b261f7d0a0739ec807ab"
 
+[[package]]
+name = "linux-raw-sys"
+version = "0.12.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "32a66949e030da00e8c7d4434b251670a91556f4144941d37452769c25d58a53"
+
 [[package]]
 name = "litemap"
 version = "0.8.1"
@@ -669,6 +716,27 @@ dependencies = [
  "windows-sys 0.61.2",
 ]
 
+[[package]]
+name = "nibble_vec"
+version = "0.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "77a5d83df9f36fe23f0c3648c6bbb8b0298bb5f1939c8f2704431371f4b84d43"
+dependencies = [
+ "smallvec",
+]
+
+[[package]]
+name = "nix"
+version = "0.29.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "71e2746dc3a24dd78b3cfcb7be93368c6de9963d30f43a6a73998a9cf4b17b46"
+dependencies = [
+ "bitflags",
+ "cfg-if",
+ "cfg_aliases",
+ "libc",
+]
+
 [[package]]
 name = "num-conv"
 version = "0.2.1"
@@ -888,6 +956,16 @@ version = "5.3.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "69cdb34c158ceb288df11e18b4bd39de994f6657d83847bdffdbd7f346754b0f"
 
+[[package]]
+name = "radix_trie"
+version = "0.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c069c179fcdc6a2fe24d8d18305cf085fdbd4f922c041943e203685d6a1c58fd"
+dependencies = [
+ "endian-type",
+ "nibble_vec",
+]
+
 [[package]]
 name = "rand"
 version = "0.9.2"
@@ -1037,10 +1115,23 @@ dependencies = [
  "bitflags",
  "errno",
  "libc",
- "linux-raw-sys",
+ "linux-raw-sys 0.4.15",
  "windows-sys 0.52.0",
 ]
 
+[[package]]
+name = "rustix"
+version = "1.1.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b6fe4565b9518b83ef4f91bb47ce29620ca828bd32cb7e408f0062e9930ba190"
+dependencies = [
+ "bitflags",
+ "errno",
+ "libc",
+ "linux-raw-sys 0.12.1",
+ "windows-sys 0.61.2",
+]
+
 [[package]]
 name = "rustls"
 version = "0.23.37"
@@ -1092,12 +1183,35 @@ dependencies = [
  "crossterm",
  "pulldown-cmark",
  "runtime",
+ "rustyline",
  "serde_json",
  "syntect",
  "tokio",
  "tools",
 ]
 
+[[package]]
+name = "rustyline"
+version = "15.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2ee1e066dc922e513bda599c6ccb5f3bb2b0ea5870a579448f2622993f0a9a2f"
+dependencies = [
+ "bitflags",
+ "cfg-if",
+ "clipboard-win",
+ "fd-lock",
+ "home",
+ "libc",
+ "log",
+ "memchr",
+ "nix",
+ "radix_trie",
+ "unicode-segmentation",
+ "unicode-width",
+ "utf8parse",
+ "windows-sys 0.59.0",
+]
+
 [[package]]
 name = "ryu"
 version = "1.0.23"
@@ -1525,6 +1639,12 @@ version = "1.0.24"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e6e4313cd5fcd3dad5cafa179702e2b244f760991f45397d14d4ebf38247da75"
 
+[[package]]
+name = "unicode-segmentation"
+version = "1.13.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9629274872b2bfaf8d66f5f15725007f635594914870f65218920345aa11aa8c"
+
 [[package]]
 name = "unicode-width"
 version = "0.2.2"
@@ -1555,6 +1675,12 @@ version = "1.0.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "b6c140620e7ffbb22c2dee59cafe6084a59b5ffc27a8859a5f0d494b5d52b6be"
 
+[[package]]
+name = "utf8parse"
+version = "0.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "06abde3611657adf66d383f00b093d7faecc7fa57071cce2578660c9f1010821"
+
 [[package]]
 name = "version_check"
 version = "0.9.5"
@@ -1725,6 +1851,15 @@ dependencies = [
  "windows-targets 0.52.6",
 ]
 
+[[package]]
+name = "windows-sys"
+version = "0.59.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1e38bc4d79ed67fd075bcc251a1c39b32a1776bbe92e5bef1f0bf1f8c531853b"
+dependencies = [
+ "windows-targets 0.52.6",
+]
+
 [[package]]
 name = "windows-sys"
 version = "0.60.2"