feat(reasoning-effort): persisted per-conversation + per-turn override, threaded to providers

- conversation-store: get/setReasoningEffort (own key space, mirrors cwd)
- session-orchestrator: resolveReasoningEffort (override -> stored -> 'high'),
  StartTurnInput.reasoningEffort, warm() parity (cache-safe)
- transport-http: /chat validation (400 on bad level) + GET/PUT
  /conversations/:id/reasoning-effort
- transport-ws: chat.send threading + validation
- cli: --effort <low|medium|high|xhigh|max>

993 vitest + 189 bun tests green; typecheck + biome clean.

1 files changed, 43 insertions, 0 deletions

diff --git a/packages/cli/src/args.test.ts b/packages/cli/src/args.test.ts
index 02b9e9b..ce278bb 100644
--- a/packages/cli/src/args.test.ts
+++ b/packages/cli/src/args.test.ts
@@ -49,6 +49,7 @@ describe("parseArgs", () => {
 				file: undefined,
 				cwd: undefined,
 				conversationId: undefined,
+				reasoningEffort: undefined,
 				showReasoning: false,
 			});
 		});
@@ -63,6 +64,7 @@ describe("parseArgs", () => {
 				file: "foo.txt",
 				cwd: undefined,
 				conversationId: undefined,
+				reasoningEffort: undefined,
 				showReasoning: false,
 			});
 		});
@@ -96,10 +98,51 @@ describe("parseArgs", () => {
 				file: undefined,
 				cwd: "/tmp",
 				conversationId: "abc",
+				reasoningEffort: undefined,
 				showReasoning: true,
 			});
 		});
 
+		it("parses --effort high", () => {
+			const result = parseArgs(["m", "--text", "x", "--effort", "high"], { defaultServer });
+			expect(result).toEqual({
+				kind: "chat",
+				server: "http://localhost:24203",
+				modelName: "m",
+				text: "x",
+				file: undefined,
+				cwd: undefined,
+				conversationId: undefined,
+				reasoningEffort: "high",
+				showReasoning: false,
+			});
+		});
+
+		it.each(["low", "medium", "high", "xhigh", "max"] as const)("accepts --effort %s", (level) => {
+			const result = parseArgs(["m", "--text", "x", "--effort", level], { defaultServer });
+			expect(result.kind).toBe("chat");
+			if (result.kind === "chat") expect(result.reasoningEffort).toBe(level);
+		});
+
+		it("errors when --effort has no value", () => {
+			const result = parseArgs(["m", "--text", "x", "--effort"], { defaultServer });
+			expect(result.kind).toBe("error");
+			if (result.kind === "error") expect(result.message).toContain("--effort requires a value");
+		});
+
+		it("errors on invalid effort level", () => {
+			const result = parseArgs(["m", "--text", "x", "--effort", "banana"], { defaultServer });
+			expect(result.kind).toBe("error");
+			if (result.kind === "error") {
+				expect(result.message).toContain("banana");
+				expect(result.message).toContain("low");
+				expect(result.message).toContain("medium");
+				expect(result.message).toContain("high");
+				expect(result.message).toContain("xhigh");
+				expect(result.message).toContain("max");
+			}
+		});
+
 		it("errors when text and file are both missing", () => {
 			const result = parseArgs(["my-model"], { defaultServer });
 			expect(result.kind).toBe("error");