Embed fonts from repo instead of ~/.local/share/fonts

Move BrassMono font files into fonts/ and use a repo-relative
include_bytes! path so the build is self-contained. Add CLAUDE.md.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

CLAUDE.md

@@ -0,0 +1,33 @@
+# CLAUDE.md
+
+This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
+
+## Project
+
+Redactor is a two-pane text redaction GUI built in Rust with eframe/egui. Users paste text in the left panel, select regions and press Ctrl+R to toggle redaction, and the right panel shows a live preview with redacted regions replaced by block characters (U+2588). The entire application lives in `src/main.rs`.
+
+## Build & Run
+
+```bash
+cargo build              # debug build
+cargo build --release    # release build
+cargo run                # run the app
+```
+
+Nix flake provides the dev environment (Rust toolchain + native deps for egui). Direnv auto-loads it via `.envrc`.
+
+## Architecture
+
+All logic is in `src/main.rs` (~490 lines) in the `RedactorApp` struct:
+
+- **State**: source text (`String`) + sorted non-overlapping byte ranges (`Vec<Range<usize>>`) of redactions
+- **Left panel**: editable `TextEdit` with redacted regions highlighted via `LayoutJob` text formatting
+- **Right panel**: read-only preview where redacted bytes become full-block characters, preserving whitespace
+- **Reconciliation**: when source text is edited, `reconcile_redactions` adjusts byte ranges by detecting unchanged prefix/suffix regions
+- **Range operations**: `add_redaction` merges overlapping ranges; `remove_redaction` splits ranges; all operations snap to UTF-8 character boundaries
+
+## UI
+
+- Nord color palette (dark theme) with BrassMonoCode monospace font (bundled .ttf files, embedded at compile time)
+- Keyboard: Ctrl+R toggles redaction on selection, Cmd+Q quits
+- Toolbar has keyboard help and "Copy Redacted" button