♻️ Replace miette and owo-colors with codespan-reporting (#118)

## Summary
- Replace `miette` with `codespan-reporting` for error diagnostics
- Replace `owo-colors` with `yansi` (already a workspace dependency) for
syntax highlighting
- Use codespan's `.with_code()` for error phase labels (e.g.
`error[lexer]`, `error[vm]`)
- Convert `InterpreterError` directly to codespan `Diagnostic`, removing
the intermediate `NdcReport` / `Report` struct
- Fix disassemble error path to pass source code through so span labels
render correctly
- Document branch naming convention in CLAUDE.md

## Test plan
- [x] All 267 tests pass
- [x] Clippy clean
- [x] `cargo fmt` applied
- [x] Manual check: run a script with an error and verify the diagnostic
renders correctly
- [x] Manual check: REPL error rendering
- [x] Manual check: `ndc highlight` subcommand

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-authored-by: Claude Opus 4.6 <[email protected]>

Author: timfennis

CLAUDE.md

@@ -64,6 +64,7 @@ Source → [Lexer] → Tokens → [Parser] → AST → [Analyser] → Annotated
 ### Git Workflow
 - Prefer short commit messages, only use multiple lines in case of unrelated changes
 - Pull request titles must start with an emoji
+- Branch names use category prefixes: `feature/`, `bugfix/`, `housekeeping/`, etc.
 
 ### Crate Layout
 

Cargo.lock

@@ -33,7 +33,6 @@ ndc_stdlib = { path = "ndc_stdlib" }
 num = "0.4.3"
 once_cell = "1.21.3"
 ordered-float = "5.1.0"
-owo-colors = { version = "4.3.0", features = ["supports-colors"] }
 yansi = { version = "1.0.1", features = ["detect-tty", "detect-env"] }
 rand = "0.10.0"
 rand_chacha = "0.10.0"

Cargo.toml

@@ -13,13 +13,12 @@ anyhow.workspace = true
 clap.workspace = true
 itertools.workspace = true
 strsim.workspace = true
-miette = { version = "7.6.0", features = ["fancy"] }
+codespan-reporting = "0.11.1"
 ndc_lexer.workspace = true
 ndc_interpreter.workspace = true
 ndc_stdlib.workspace = true
 ndc_core.workspace = true
 ndc_lsp.workspace = true
-owo-colors.workspace = true
 yansi.workspace = true
 rustyline.workspace = true
 termimad = "0.34.1"