test: add pre/before hook tests for runtime

Add tests for pre-hook execution in buildContext phase:
- pre hook runs and captures output
- before hook as alias for pre
- pre takes precedence over before
- pre hook output prepended to body
- post/after hooks stored for execution phase
- hooks excluded from CLI args

Author: johnlindquist

src/runtime.test.ts

@@ -143,6 +143,106 @@ Hello`);
       expect(context.frontmatter).toEqual({});
       expect(context.rawBody).toBe("Just body");
     });
+
+    it("runs pre hook and captures output", async () => {
+      const filePath = join(tempDir, "prehook.claude.md");
+      await writeFile(filePath, `---
+pre: echo "pre-hook output"
+---
+Body content`);
+
+      const runtime = createRuntime();
+      const resolved = await runtime.resolve(filePath);
+      const context = await runtime.buildContext(resolved);
+
+      expect(context.preHookOutput).toBe("pre-hook output\n");
+    });
+
+    it("runs before hook (alias for pre)", async () => {
+      const filePath = join(tempDir, "beforehook.claude.md");
+      await writeFile(filePath, `---
+before: echo "before-hook output"
+---
+Body content`);
+
+      const runtime = createRuntime();
+      const resolved = await runtime.resolve(filePath);
+      const context = await runtime.buildContext(resolved);
+
+      expect(context.preHookOutput).toBe("before-hook output\n");
+    });
+
+    it("pre hook takes precedence over before", async () => {
+      const filePath = join(tempDir, "prebefore.claude.md");
+      await writeFile(filePath, `---
+pre: echo "pre wins"
+before: echo "before loses"
+---
+Body content`);
+
+      const runtime = createRuntime();
+      const resolved = await runtime.resolve(filePath);
+      const context = await runtime.buildContext(resolved);
+
+      expect(context.preHookOutput).toBe("pre wins\n");
+    });
+
+    it("throws error when pre hook fails", async () => {
+      const filePath = join(tempDir, "badhook.claude.md");
+      await writeFile(filePath, `---
+pre: exit 1
+---
+Body content`);
+
+      const runtime = createRuntime();
+      const resolved = await runtime.resolve(filePath);
+
+      await expect(runtime.buildContext(resolved)).rejects.toThrow("Pre hook failed");
+    });
+
+    it("captures post hook command for later", async () => {
+      const filePath = join(tempDir, "posthook.claude.md");
+      await writeFile(filePath, `---
+post: echo "done"
+---
+Body content`);
+
+      const runtime = createRuntime();
+      const resolved = await runtime.resolve(filePath);
+      const context = await runtime.buildContext(resolved);
+
+      expect(context.postHookCommand).toBe("echo \"done\"");
+    });
+
+    it("after hook is alias for post", async () => {
+      const filePath = join(tempDir, "afterhook.claude.md");
+      await writeFile(filePath, `---
+after: echo "after done"
+---
+Body content`);
+
+      const runtime = createRuntime();
+      const resolved = await runtime.resolve(filePath);
+      const context = await runtime.buildContext(resolved);
+
+      expect(context.postHookCommand).toBe("echo \"after done\"");
+    });
+
+    it("pre hook uses env vars from frontmatter", async () => {
+      const filePath = join(tempDir, "hookenv.claude.md");
+      await writeFile(filePath, `---
+env:
+  MY_VAR: hello
+pre: echo "$MY_VAR world"
+---
+Body`);
+
+      const runtime = createRuntime();
+      const resolved = await runtime.resolve(filePath);
+      const context = await runtime.buildContext(resolved);
+
+      expect(context.preHookOutput).toBe("hello world\n");
+    });
   });
 
   describe("Template Phase", () => {
@@ -324,6 +424,30 @@ Test prompt`);
       // Cleanup should not throw for local files
       await expect(runtime.cleanup()).resolves.toBeUndefined();
     });
+
+    it("prepends pre hook output to body in dry run", async () => {
+      const filePath = join(tempDir, "preoutput.claude.md");
+      await writeFile(filePath, `---
+pre: echo "HOOK OUTPUT"
+---
+Body content`);
+
+      const runtime = createRuntime();
+      const resolved = await runtime.resolve(filePath);
+      const context = await runtime.buildContext(resolved);
+      const processed = await runtime.processTemplate(context);
+
+      // Verify pre-hook output is captured
+      expect(context.preHookOutput).toBe("HOOK OUTPUT\n");
+
+      // Simulate what execute does with pre-hook output
+      let finalBody = processed.body;
+      if (context.preHookOutput) {
+        finalBody = `${context.preHookOutput.trim()}\n\n${finalBody}`;
+      }
+
+      expect(finalBody).toBe("HOOK OUTPUT\n\nBody content");
+    });
   });
 
   describe("createRuntime factory", () => {