fix(cli): ASCII glyph fallback for Windows console mojibake (#168) (#178)

The shimmer progress renderer writes from a worker thread via
`fs.writeSync(1, ...)` to keep the animation smooth while the main
thread is busy in SQLite. That path bypasses Node's TTY-aware
UTF-8->codepage conversion on Windows, so glyphs like `|`/`<>`/`-`
were emitted as raw UTF-8 bytes and reinterpreted by the console's
OEM codepage (CP437, CP936, ...), producing strings like
`鋍?[0m 鉒?[0m Scanning files 鈥?N found`.

Add `src/ui/glyphs.ts` with `supportsUnicode()` detection plus
matched Unicode + ASCII glyph sets, and route all CLI/shimmer
output through `getGlyphs()`. Defaults: ASCII on Windows and on
Linux kernel consoles (`TERM=linux`), Unicode everywhere else.
`CODEGRAPH_UNICODE=1` and `CODEGRAPH_ASCII=1` are escape hatches.

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/bin/node-version-check.ts

@@ -13,9 +13,12 @@
  * unsupported Node.js major version (currently 25+). Pinned via unit
  * test so the recovery commands and override instructions can't be
  * silently stripped by future edits.
+ *
+ * Uses ASCII glyphs to stay readable on Windows OEM-codepage consoles
+ * (see ../ui/glyphs.ts for the rationale).
  */
 export function buildNode25BlockBanner(nodeVersion: string): string {
-  const sep = '─'.repeat(72);
+  const sep = '-'.repeat(72);
   return [
     sep,
     `[CodeGraph] Unsupported Node.js version: ${nodeVersion}`,
@@ -29,7 +32,7 @@ export function buildNode25BlockBanner(nodeVersion: string): string {
     '  nvm install 22 && nvm use 22                          # nvm',
     '  brew install node@22 && brew link --overwrite --force node@22  # Homebrew',
     '',
-    'To override (NOT recommended — you will likely OOM):',
+    'To override (NOT recommended - you will likely OOM):',
     '  CODEGRAPH_ALLOW_UNSAFE_NODE=1 codegraph ...',
     sep,
   ].join('\n');