Merge master into refactor/envoverrides-tmux-export

Resolved conflict in src/web/public/session-ui.js by keeping this
PR's buildEnvOverrides() helper — it already covers both
CLAUDE_CODE_EXPERIMENTAL_AGENT_TEAMS (this PR) and
CLAUDE_CODE_EFFORT_LEVEL (added in #73), so the master-side inline
block is fully replaced.

Also fixed test/session-manager.test.ts MockSession to add a
getEnvOverridesForPersist() stub — without it,
SessionManager.updateSessionState's new call breaks 19 tests with
"TypeError: session.getEnvOverridesForPersist is not a function".

Verified: typecheck, lint, format:check, build, and
test/{session-manager,session-state,tmux-manager,tmux-restart-recovery}.test.ts
all pass.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/web/schemas.ts

@@ -268,6 +268,7 @@ export const SettingsUpdateSchema = z
     tunnelEnabled: z.boolean().optional(),
     tabTwoRows: z.boolean().optional(),
     agentTeamsEnabled: z.boolean().optional(),
+    thinkingEffort: z.string().max(20).optional(),
     // UI visibility
     showFontControls: z.boolean().optional(),
     showSystemStats: z.boolean().optional(),