fix: reconcile Fusion two-segment skill names with pi-coding-agent bare names

pi-coding-agent sets Skill.name to the parent directory (e.g. 'web-research'),
while Fusion uses two-segment names everywhere (e.g. 'web-research/SKILL.md')
from extractSkillName(), normalizeAgentSkills(), and toggleExecutionSkill().

The previous fix (c9043519) correctly switched matching from skill.filePath to
skill.name, but that only works when both sides use the same format. Since they
don't, all pattern/requested-name comparisons still failed, producing the
spurious 'not found in discovered skills' warnings.

Fix: add bareSkillName() helper that strips the /SKILL.md suffix before
comparison. Applied to all five comparison points in skill-resolver.ts:
  - skillNameMatches() (pattern filtering)
  - requestedSkillNames set lookup (name filtering)
  - hasDiscoveredMatch() (configured-pattern diagnostic)
  - discoveredBareNamesLower (requested-name diagnostic)
  - excluded-path discovery check

packages/engine/src/__tests__/skill-resolver.test.ts

@@ -870,5 +870,83 @@ describe("createSkillsOverrideFromSelection", () => {
       );
       expect(missingWarnings).toHaveLength(0);
     });
+
+    it("matches Fusion two-segment patterns against pi-coding-agent bare skill names", () => {
+      // Fusion's toggleExecutionSkill saves patterns like "+web-research/SKILL.md"
+      // and normalizeAgentSkills extracts "web-research/SKILL.md" from full IDs.
+      // But pi-coding-agent sets Skill.name to just the directory name: "web-research".
+      // This test verifies the cross-format matching works.
+      const dir = createMockProjectDir({
+        skills: ["+web-research/SKILL.md"],
+      });
+
+      const resolvedSkills = resolveSessionSkills({
+        projectRootDir: dir,
+        // Simulates what normalizeAgentSkills produces from "auto::skills/web-research/SKILL.md"
+        requestedSkillNames: ["web-research/SKILL.md"],
+        sessionPurpose: "triage",
+      });
+
+      const override = createSkillsOverrideFromSelection(resolvedSkills, {
+        requestedSkillNames: resolvedSkills.allowedSkillPaths.size > 0
+          ? ["web-research/SKILL.md"]
+          : undefined,
+        sessionPurpose: "triage",
+      });
+
+      // pi-coding-agent discovers skills with bare directory names
+      const base = {
+        skills: [
+          { name: "web-research", filePath: "/home/user/.pi/agent/skills/web-research/SKILL.md", description: "Web search", baseDir: "/home/user/.pi/agent/skills/web-research", sourceInfo: {} as any, disableModelInvocation: false },
+          { name: "paperclip", filePath: "/home/user/.pi/agent/skills/paperclip/SKILL.md", description: "Paperclip", baseDir: "/home/user/.pi/agent/skills/paperclip", sourceInfo: {} as any, disableModelInvocation: false },
+        ],
+        diagnostics: [],
+      };
+
+      const result = override(base);
+
+      // web-research should match despite the naming mismatch
+      expect(result.skills).toHaveLength(1);
+      expect(result.skills[0].name).toBe("web-research");
+
+      // No spurious "not found" warnings
+      const notFoundWarnings = result.diagnostics.filter(d =>
+        d.type === "warning" && d.message.includes("not found")
+      );
+      expect(notFoundWarnings).toHaveLength(0);
+    });
+
+    it("exclusion patterns with /SKILL.md suffix correctly exclude pi-discovered skills", () => {
+      const dir = createMockProjectDir({
+        skills: ["+web-research/SKILL.md", "-paperclip/SKILL.md"],
+      });
+
+      const resolvedSkills = resolveSessionSkills({
+        projectRootDir: dir,
+      });
+
+      const override = createSkillsOverrideFromSelection(resolvedSkills, {
+        sessionPurpose: "executor",
+      });
+
+      const base = {
+        skills: [
+          { name: "web-research", filePath: "/home/user/.pi/agent/skills/web-research/SKILL.md", description: "Web search", baseDir: "", sourceInfo: {} as any, disableModelInvocation: false },
+          { name: "paperclip", filePath: "/home/user/.pi/agent/skills/paperclip/SKILL.md", description: "Paperclip", baseDir: "", sourceInfo: {} as any, disableModelInvocation: false },
+        ],
+        diagnostics: [],
+      };
+
+      const result = override(base);
+
+      expect(result.skills).toHaveLength(1);
+      expect(result.skills[0].name).toBe("web-research");
+
+      // Should have a "disabled" diagnostic for paperclip (exists but excluded)
+      const disabledWarning = result.diagnostics.find(d =>
+        d.message.includes("disabled") && d.message.includes("paperclip")
+      );
+      expect(disabledWarning).toBeDefined();
+    });
   });
 });