feat: syntax-highlighted code blocks + fuzzy / @-file prompt autocomplete

CHANGELOG.md

@@ -8,6 +8,32 @@ versioning: [SemVer](https://semver.org/spec/v2.0.0.html).
 
 ### Added
 
+- **Prompt history + undo/redo** — `Up`/`Down` in the prompt recall previously
+  submitted messages, shell-style: recall triggers only at the editor's
+  vertical edges (`Up` on the first row, `Down` on the last) so multi-line
+  cursor movement is unaffected, and stepping back down past the newest entry
+  restores your in-progress draft. History is de-duplicated and capped.
+  `Ctrl+Z` / `Ctrl+Y` undo / redo prompt edits.
+
+- **Syntax-highlighted code blocks** — fenced code in assistant markdown is now
+  highlighted by language via `syntect` (pure-Rust `fancy-regex` engine, no C
+  toolchain). Common LLM fence tags (`rust`, `python`, `ts`, `bash`, …) are
+  normalised to the right syntax; unknown languages fall back to the previous
+  flat-green rendering. Highlighting is stateful across a block and paid once
+  per message version through the existing render cache.
+
+- **`@`-file mention autocomplete** — typing `@` in the prompt opens a
+  filesystem palette (relative to the focused session's workdir), fuzzy-ranked
+  against what you've typed. `Tab` completes to the top hit: directories keep a
+  trailing `/` so you can keep drilling, files get a trailing space. Descends
+  subdirectories (`@src/re…`) and reveals dotfiles only when you type a leading
+  dot.
+
+- **Fuzzy slash-command matching** — the `/` command palette and `Tab`
+  completion now rank by a fuzzy subsequence score (consecutive-run and
+  word-boundary bonuses, gap penalties) instead of a strict prefix, so `/expsn`
+  finds `/export` and `Tab` always commits the best match.
+
 - **Multi-provider sessions** (pairs with the daemon's pi backend +
   mid-session switching): `/new <name> [workdir] --provider <id>` creates a
   session on a specific backend, `/provider <id>` switches the focused

Cargo.toml

@@ -38,6 +38,10 @@ tui-textarea = "0.7"
 # Utility
 anyhow = "1"
 unicode-width = "0.2"
+# Syntax highlighting for fenced code blocks. `default-fancy` swaps the
+# oniguruma C dependency for the pure-Rust fancy-regex engine, so the build
+# stays cross-compile-friendly with no C toolchain requirement.
+syntect = { version = "5", default-features = false, features = ["default-fancy"] }
 thiserror = "2"
 tracing = "0.1"
 tracing-subscriber = { version = "0.3", features = ["env-filter"] }

README.md

@@ -140,6 +140,9 @@ cargo test -p codeoid-tui state::       # reducer tests (no Tokio, no Ratatui)
 | `Ctrl+X` / `.`         | Interrupt — unconditional aliases   |
 | `Enter`                | Send prompt                         |
 | `Shift+Enter` / `Ctrl+J` | Newline in prompt                 |
+| `Tab` (in prompt)      | Autocomplete — slash-command after `/`, or a file after `@` (fuzzy-ranked; directories keep drilling) |
+| `↑` / `↓` (in prompt)  | Recall previous / next submitted prompt (at the editor's top / bottom edge) |
+| `Ctrl+Z` / `Ctrl+Y`    | Undo / redo prompt edits             |
 | `←` / `→`, `p` / `n`   | Prev / next session                 |
 | `y` / `d`              | Approve / deny pending tool         |
 | `m`                    | Cycle execution mode                |

crates/codeoid-tui/Cargo.toml

@@ -32,3 +32,4 @@ tracing-subscriber = { workspace = true }
 clap = { workspace = true }
 chrono = { workspace = true }
 unicode-width = { workspace = true }
+syntect = { workspace = true }