fix: port prepareClaudePromptBundle flow to claude_k8s adapter (FAR-11)

K8s Job pods were starting without the Paperclip skill loaded, so agents
could not find their heartbeat procedure and reported "no issue content in
my workspace" on every wake. Root cause: claude_local materialises skills
into a PVC-backed prompt-bundle directory and passes --add-dir to Claude,
but claude_k8s did neither.

Changes:
- Add src/server/prompt-cache.ts with prepareClaudePromptBundle (ported
  from adapter-claude-local). Writes skill symlinks and the agent's
  instructions file into a content-addressed bundle directory under the
  shared PVC (/paperclip/instances/.../claude-prompt-cache/<hash>/).
- execute.ts: read desired skills and instructions file before building
  the Job manifest, then call prepareClaudePromptBundle and pass the
  resulting bundle to buildJobManifest.
- job-manifest.ts: accept optional promptBundle in JobBuildInput; when
  present, pass --add-dir <bundle.addDir> and use bundle.instructionsFilePath
  for --append-system-prompt-file. Also fix: skip --append-system-prompt-file
  on session resumes to avoid wasting tokens on re-injection.
- skills.ts: correct the detail string to reflect actual materialisation.
- job-manifest.test.ts: add 5 new tests covering --add-dir injection,
  bundle path preference, session-resume skipping, and fallback behaviour.

Co-Authored-By: Paperclip <noreply@paperclip.ing>

src/server/execute.ts

@@ -1,5 +1,15 @@
 import type { AdapterExecutionContext, AdapterExecutionResult } from "@paperclipai/adapter-utils";
-import { asString, asNumber, asBoolean, parseObject } from "@paperclipai/adapter-utils/server-utils";
+import {
+  asString,
+  asNumber,
+  asBoolean,
+  parseObject,
+  readPaperclipRuntimeSkillEntries,
+  resolvePaperclipDesiredSkillNames,
+} from "@paperclipai/adapter-utils/server-utils";
+import fs from "node:fs/promises";
+import path from "node:path";
+import { prepareClaudePromptBundle } from "./prompt-cache.js";
 import {
   parseClaudeStreamJson,
   describeClaudeFailure,
@@ -619,6 +629,38 @@ export async function execute(ctx: AdapterExecutionContext): Promise<AdapterExec
   let namespace: string;
   let promptSecret: { name: string; namespace: string; data: Record<string, string> } | null = null;
 
+  // Prepare the prompt bundle (skills + instructions) on the server filesystem.
+  // The K8s Job pod mounts the same PVC at /paperclip, so bundle paths written
+  // here are accessible inside the pod at the identical absolute path.
+  const skillEntries = await readPaperclipRuntimeSkillEntries(config, import.meta.dirname ?? __dirname);
+  const desiredSkillNames = new Set(resolvePaperclipDesiredSkillNames(config, skillEntries));
+  const desiredSkills = skillEntries.filter((e) => desiredSkillNames.has(e.key));
+  const instructionsFilePath = asString(config.instructionsFilePath, "").trim();
+  const instructionsFileDir = instructionsFilePath ? `${path.dirname(instructionsFilePath)}/` : "";
+  let instructionsContents: string | null = null;
+  if (instructionsFilePath) {
+    try {
+      const raw = await fs.readFile(instructionsFilePath, "utf-8");
+      const pathDirective =
+        `\nThe above agent instructions were loaded from ${instructionsFilePath}. ` +
+        `Resolve any relative file references from ${instructionsFileDir}. ` +
+        `This base directory is authoritative for sibling instruction files such as ` +
+        `./HEARTBEAT.md, ./SOUL.md, and ./TOOLS.md; do not resolve those from the parent agent directory.`;
+      instructionsContents = raw + pathDirective;
+    } catch (err) {
+      await onLog(
+        "stderr",
+        `[paperclip] Warning: could not read agent instructions file "${instructionsFilePath}": ${err instanceof Error ? err.message : String(err)}\n`,
+      );
+    }
+  }
+  const promptBundle = await prepareClaudePromptBundle({
+    companyId: ctx.agent.companyId,
+    skills: desiredSkills,
+    instructionsContents,
+    onLog,
+  });
+
   if (reattachTarget) {
     jobName = reattachTarget.jobName;
     namespace = reattachTarget.namespace;
@@ -646,7 +688,7 @@ export async function execute(ctx: AdapterExecutionContext): Promise<AdapterExec
     await onLog("stdout", `[paperclip] Reattaching to in-flight K8s Job ${jobName} in namespace ${namespace} (prior run ${reattachTarget.priorRunId || "unknown"})\n`);
   } else {
     // Build Job manifest
-    const built = buildJobManifest({ ctx, selfPod });
+    const built = buildJobManifest({ ctx, selfPod, promptBundle });
     const job = built.job;
     jobName = built.jobName;
     namespace = built.namespace;