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/web/public/ralph-wizard.js

@@ -1032,10 +1032,9 @@ Object.assign(CodemanApp.prototype, {
     const enabledItems = config.generatedPlan?.filter(i => i.enabled);
 
     try {
-      const envOverrides = this.buildEnvOverrides(
-        this.getCaseSettings(config.caseName),
-        this.loadAppSettingsFromStorage()
-      );
+      const ralphGlobalSettings = this.loadAppSettingsFromStorage();
+      const envOverrides = this.buildEnvOverrides(this.getCaseSettings(config.caseName), ralphGlobalSettings);
+      const effort = this.getEffortSetting(ralphGlobalSettings);
       const res = await fetch('/api/ralph-loop/start', {
         method: 'POST',
         headers: { 'Content-Type': 'application/json' },
@@ -1047,6 +1046,7 @@ Object.assign(CodemanApp.prototype, {
           enableRespawn: config.enableRespawn,
           planItems: enabledItems?.length ? enabledItems : undefined,
           ...(Object.keys(envOverrides).length > 0 ? { envOverrides } : {}),
+          ...(effort ? { effort } : {}),
         }),
       });
       const data = await res.json();