Adds a "Config Directories" section under the Claude settings tab so users
can aggregate usage across multiple Claude config directories (work /
personal accounts) from the GUI. The menubar is an accessory app that
doesn't inherit the user's shell environment, so CLAUDE_CONFIG_DIRS was
previously unreachable from the app.
Rather than injecting the value as an env var into every spawned subprocess
(which would force arbitrary user paths through the shell/AppleScript
allowlist that deliberately excludes shell metacharacters), the list is
persisted to the shared ~/.config/codeburn/config.json. The CLI reads it
regardless of how it's launched, so both the menubar's data refresh and
terminal-launched `report`/`optimize` honor it consistently.
CLI: getClaudeConfigDirs() now reads a claudeConfigDirs array from config
as a fallback below the CLAUDE_CONFIG_DIRS / CLAUDE_CONFIG_DIR env vars
(env still wins for per-shell overrides), above the ~/.claude default.
Menubar: CLIClaudeConfig mirrors CLICurrencyConfig's flock-guarded write;
the Settings UI offers an add/remove list with a folder picker and forces
a refresh on edit.
