[MCP] refactor(samples): use configureMcpCatalog and resolve @a2ui/catalog-mcp from dist

[josemontespg]

Summary

Moves the two community MCP sample clients to the v1.0 entry point of @a2ui/catalog-mcp introduced in the parent PR, and resolves @a2ui/catalog-mcp, @a2ui/lit and @a2ui/web_core from the monorepo dist/ instead of compiling the catalog from source against the npm packages.

Changes

• samples/community/mcp/a2ui-over-mcp-{filesystem,recipe}/client/app.ts: register CallMcpToolImplementation (the filesystem sample next to its own data functions) and configure the host with configureMcpCatalog.
• vite.config.ts, tsconfig.json, package.json of both clients: resolve the three packages from the repository dist/ (TODO Clean up folder samples/community. #1698); the sample tests follow the monorepo Catalog/DataContext constructors.
• .github/workflows/community_code.yml: build @a2ui/catalog-mcp and @a2ui/lit at the repository root before the community checks.

Verification

• yarn test in both sample clients against a fresh @a2ui/catalog-mcp build (64 and 11 tests).
• python3 scripts/fix_licenses.py --check.

Related to #3157

[gemini-code-assist]

Code Review

This pull request updates the MCP client and catalog configuration across the community samples, transitioning from using createMcpCatalogFunctions to CallMcpToolImplementation and configureMcpCatalog. It also updates Catalog constructors to include a version parameter, modifies getClientCapabilities calls, and refactors monorepo aliases in tsconfig.json and vite.config.ts to use built packages. Feedback on these changes highlights two main issues: first, removing @a2ui/lit leaves the filesystem client without an explicit dependency on lit (which is still directly used); second, getMcpClientForTool should include a defensive check to throw an error if this.mcpClient is not yet initialized, preventing potential runtime errors.

[gemini-code-assist]

With the removal of @a2ui/lit from the dependencies, this project no longer has a direct dependency on lit, even though A2uiFilesystemApp extends LitElement and uses other Lit features. To prevent potential resolution issues (especially in strict package managers), lit should be explicitly declared as a dependency, similar to how it is done in the recipe client.

[gemini-code-assist]

If this.mcpClient is not yet initialized or connection fails, getMcpClientForTool will return undefined. This can lead to runtime TypeErrors when a tool is invoked. Consider adding a defensive check to throw a descriptive error if the client is not initialized.

      getMcpClientForTool: () => {
        if (!this.mcpClient) {
          throw new Error('MCP client is not initialized');
        }
        return this.mcpClient;
      },

[josemontespg]

Folded into #3186: the community samples are the in-repo consumers of the API change there, and the stack was red in between (Community Code CI compiled the samples against an entry point that no longer exported createMcpCatalogFunctions).