Add Claude Code settings infrastructure, TUI mode, session naming, and global defaults

Adds first-class support for Claude Code CLI features (2.1.71-2.1.110):

- New ClaudeCodeSettings struct with per-project and global defaults for
  TUI mode, effort level, focus mode, thinking summaries, session recap,
  auto-scroll, env scrub, and 1-hour prompt caching
- Settings injected as env vars (CLAUDE_CODE_NO_FLICKER, etc.) and
  ~/.claude/settings.json entries via entrypoint.sh merge block
- New ClaudeCodeSettingsModal component for configuring settings
- Session naming support (-n flag passed to claude CLI, shown in tabs)
- Relaxed reserved prefix filter: CLAUDE_CODE_* env vars now allowed in
  custom env vars UI for power users
- Global SSH key path, git name, and git email now used as fallbacks
  when per-project values are not set, with UI in SettingsPanel
- Fingerprint-based change detection triggers container recreation when
  Claude Code settings change
- Updated README, HOW-TO-USE, and CLAUDE.md documentation

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

app/src/hooks/useTerminal.ts

@@ -17,10 +17,10 @@ export function useTerminal() {
     );
 
   const open = useCallback(
-    async (projectId: string, projectName: string, sessionType: "claude" | "bash" = "claude") => {
+    async (projectId: string, projectName: string, sessionType: "claude" | "bash" = "claude", sessionName?: string) => {
       const sessionId = crypto.randomUUID();
-      await commands.openTerminalSession(projectId, sessionId, sessionType);
-      addSession({ id: sessionId, projectId, projectName, sessionType });
+      await commands.openTerminalSession(projectId, sessionId, sessionType, sessionName);
+      addSession({ id: sessionId, projectId, projectName, sessionType, sessionName: sessionName ?? null });
       return sessionId;
     },
     [addSession],