fix: skills not bundled and resumeLastSession ignored (FAR-56, FAR-57)

Two bugs prevented skill content from reaching K8s Job prompts, and
resumeLastSession: false was silently ignored.

Skills fix (execute.ts, FAR-57):
- Add /paperclip/.claude/skills as additional candidate to
  readPaperclipRuntimeSkillEntries — the relative candidates in
  adapter-utils don't resolve to the PVC-mounted skills home
- Read entry.source/SKILL.md instead of entry.source (which is a
  directory path); fall back to source directly for file-based entries
- Mock readPaperclipRuntimeSkillEntries in execute.test.ts to prevent
  real SKILL.md reads from delaying fake-timer registration

Session fix (job-manifest.ts, FAR-56):
- Gate --session flag on asBoolean(config.resumeLastSession, true)
  so setting resumeLastSession: false actually stops session resumption
- Default true preserves existing behaviour for agents without config

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/server/execute.test.ts

@@ -16,6 +16,13 @@ vi.mock("./job-manifest.js", () => ({
   LARGE_PROMPT_THRESHOLD_BYTES: 256 * 1024,
 }));
 
+// Prevent skill loading from reading real SKILL.md files during tests — the
+// real filesystem read delays timer registration and breaks fake-timer tests.
+vi.mock("@paperclipai/adapter-utils/server-utils", async (importOriginal) => {
+  const actual = await importOriginal<typeof import("@paperclipai/adapter-utils/server-utils")>();
+  return { ...actual, readPaperclipRuntimeSkillEntries: vi.fn().mockResolvedValue([]) };
+});
+
 const MOCK_SELF_POD = {
   namespace: "test-ns",
   image: "test-image:latest",