fix: pass Claude prompt via stdin to avoid ENAMETOOLONG on Windows

The Claude Code adapter passed the full prompt (~44 KB with skills,
context, and memory) as a command-line argument via `-p <prompt>`.
On Windows, CreateProcessW has a 32,767-character command-line limit,
causing `spawn ENAMETOOLONG` for any agent with multiple skills or
substantial context (e.g. Wiki Keeper).

Claude Code supports reading the prompt from stdin when `-p` is used
without a positional prompt argument — the same pattern the Codex
adapter already uses with `-`.

Changes:
- src/adapters/claudeCodeAdapter.ts: remove opts.prompt from args,
  add stdinPayload to the return value
- src/adapters/types.ts: update ExecInvocation.stdinPayload comment
- src/adapters/claudeCodeAdapter.test.ts: update buildExec test
  expectations (prompt via stdinPayload, not in args)

Tested: all 252 tests pass. Manually verified on Windows 10 with
Claude Code CLI.

Co-Authored-By: Claude <noreply@anthropic.com>

package-lock.json

@@ -1,12 +1,12 @@
 {
   "name": "obsidian-agent-fleet",
-  "version": "0.13.6",
+  "version": "0.15.0",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
       "name": "obsidian-agent-fleet",
-      "version": "0.13.6",
+      "version": "0.15.0",
       "hasInstallScript": true,
       "license": "MIT",
       "dependencies": {

src/adapters/claudeCodeAdapter.test.ts

@@ -77,13 +77,14 @@ function makeBuildOptions(overrides: Partial<ExecBuildOptions> = {}): ExecBuildO
 }
 
 describe("claudeCodeAdapter.buildExec", () => {
-  it("builds the streaming invocation with -p prompt and verbose stream-json", async () => {
+  it("builds the streaming invocation with -p (prompt via stdin) and verbose stream-json", async () => {
     const inv = await claudeCodeAdapter.buildExec(makeBuildOptions());
     expect(inv.cliPath).toBe("claude");
-    expect(inv.args.slice(0, 2)).toEqual(["-p", "do the thing"]);
+    expect(inv.args[0]).toBe("-p");
     expect(inv.args).toContain("stream-json");
     expect(inv.args).toContain("--verbose");
-    expect(inv.stdinPayload).toBeUndefined();
+    expect(inv.args).not.toContain("do the thing");
+    expect(inv.stdinPayload).toBe("do the thing");
   });
 
   it("uses plain json without --verbose when not streaming", async () => {

src/adapters/claudeCodeAdapter.ts

@@ -226,7 +226,6 @@ export const claudeCodeAdapter: CliAdapter = {
   buildExec(opts: ExecBuildOptions): Promise<ExecInvocation> {
     const args = [
       "-p",
-      opts.prompt,
       "--output-format",
       opts.streaming ? "stream-json" : "json",
     ];
@@ -256,7 +255,7 @@ export const claudeCodeAdapter: CliAdapter = {
       args.push("--permission-mode", "bypassPermissions");
     }
 
-    return Promise.resolve({ cliPath: opts.settings.claudeCliPath, args });
+    return Promise.resolve({ cliPath: opts.settings.claudeCliPath, args, stdinPayload: opts.prompt });
   },
 
   parseExecOutput(stdout: string, stderr: string, streaming: boolean): ExecParseResult {

src/adapters/types.ts

@@ -27,9 +27,8 @@ export interface ExecBuildOptions {
 export interface ExecInvocation {
   cliPath: string;
   args: string[];
-  /** Written to stdin right after spawn, then stdin is closed. Codex takes
-   *  the prompt this way (positional `-`) to dodge argv length limits;
-   *  Claude takes the prompt via `-p` and needs nothing on stdin. */
+  /** Written to stdin right after spawn, then stdin is closed. Both adapters
+   *  use this to dodge OS argv length limits (Windows: 32 767 chars). */
   stdinPayload?: string;
 }