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-tauri/src/commands/project_commands.rs

@@ -338,6 +338,10 @@ pub async fn start_project_container(
                 &settings.global_custom_env_vars,
                 settings.timezone.as_deref(),
                 &enabled_mcp,
+                settings.global_claude_code_settings.as_ref(),
+                settings.default_ssh_key_path.as_deref(),
+                settings.default_git_user_name.as_deref(),
+                settings.default_git_user_email.as_deref(),
             ).await.unwrap_or(false);
 
             if needs_recreate {
@@ -370,6 +374,10 @@ pub async fn start_project_container(
                     settings.timezone.as_deref(),
                     &enabled_mcp,
                     network_name.as_deref(),
+                    settings.global_claude_code_settings.as_ref(),
+                    settings.default_ssh_key_path.as_deref(),
+                    settings.default_git_user_name.as_deref(),
+                    settings.default_git_user_email.as_deref(),
                 ).await?;
                 emit_progress(&app_handle, &project_id, "Starting container...");
                 docker::start_container(&new_id).await?;
@@ -403,6 +411,10 @@ pub async fn start_project_container(
                 settings.timezone.as_deref(),
                 &enabled_mcp,
                 network_name.as_deref(),
+                settings.global_claude_code_settings.as_ref(),
+                settings.default_ssh_key_path.as_deref(),
+                settings.default_git_user_name.as_deref(),
+                settings.default_git_user_email.as_deref(),
             ).await?;
             emit_progress(&app_handle, &project_id, "Starting container...");
             docker::start_container(&new_id).await?;