feat: inject effort as soft default via CLI flags instead of env var (#104)

CLAUDE_CODE_EFFORT_LEVEL hard-locks effort for the whole session and makes
Claude reject in-session /effort switching (incl. ultracode). Carry effort
as a dedicated payload field instead, injected at spawn as a soft default:

- regular levels (incl. max) -> claude --effort <level>
  (the settings effortLevel key is enum([low,medium,high,xhigh]) with
  .catch(undefined), so max would be silently dropped there)
- ultracode -> claude --settings '{"ultracode":true}'
  (dedicated boolean settings key, rejected by the --effort flag)

Changes:
- add effort enum field to create/quick-start/ralph-loop schemas and thread
  it through Session -> CreateSessionOptions/RespawnPaneOptions -> spawn
- buildEffortCliArgs() in session-cli-builder, shared by tmux spawn command
  and direct-PTY fallback args
- frontend: buildEnvOverrides() no longer emits CLAUDE_CODE_EFFORT_LEVEL;
  validated effort goes into payloads via getEffortSetting()
- settings UI: add Ultracode option to the Thinking Effort dropdown
- legacy migration: Session constructor extracts CLAUDE_CODE_EFFORT_LEVEL
  from persisted envOverrides; applyEnvOverrides() unsets the stale tmux
  session var so respawned panes are no longer locked
- tests: test/effort-injection.test.ts (13 cases)

Co-authored-by: Teigen <teigenzhang@gmail.com>

src/types/session.ts

@@ -40,6 +40,21 @@ export type ClaudeMode = 'dangerously-skip-permissions' | 'normal' | 'allowedToo
 /** Session mode: which CLI backend a session runs */
 export type SessionMode = 'claude' | 'shell' | 'opencode';
 
+/**
+ * Valid Claude CLI effort levels (claude >= 2.1.154).
+ * `ultracode` = xhigh effort + standing dynamic-workflow orchestration; it is a
+ * separate `ultracode` settings key rather than an `effortLevel` value.
+ */
+export const EFFORT_LEVELS = ['low', 'medium', 'high', 'xhigh', 'max', 'ultracode'] as const;
+
+/** Claude CLI effort level for new sessions (soft default, switchable via /effort in-session) */
+export type EffortLevel = (typeof EFFORT_LEVELS)[number];
+
+/** Type guard: is the string a valid EffortLevel? */
+export function isEffortLevel(value: string | undefined): value is EffortLevel {
+  return value !== undefined && (EFFORT_LEVELS as readonly string[]).includes(value);
+}
+
 /** OpenCode session configuration */
 export interface OpenCodeConfig {
   /** Model identifier (e.g., "anthropic/claude-sonnet-4-5", "openai/gpt-5.2", "ollama/codellama") */
@@ -145,6 +160,8 @@ export interface SessionState {
   openCodeConfig?: OpenCodeConfig;
   /** Claude conversation session ID to resume after reboot (set by restore script) */
   resumeSessionId?: string;
+  /** Claude CLI effort level (soft default via --settings, switchable in-session via /effort) */
+  effort?: EffortLevel;
 }
 
 /**