feat(lsp): Add Prisma Language Server support

[amondnet]

Summary

Add support for the Prisma Language Server (@prisma/language-server) to @pleaseai/code-lsp package, enabling LSP features for .prisma schema files.

Problem

Prisma is a popular ORM for Node.js and TypeScript. Developers working with Prisma schema files need language intelligence features like diagnostics, completions, hover information, go-to-definition, and formatting.

Solution

Implement Prisma LSP support following the Vue LS pattern:

• Auto-download via npm to ~/.cache/dora/prisma-lsp/
• Version marker file for tracking
• Root detection via schema.prisma or prisma/schema.prisma

Tasks

• T001 [P] Add .prisma language mapping to language.ts
• T002 [P] Add PRISMA_RUNTIME_DEPS configuration
• T003 Add setupPrismaDependencies() function (depends on T002)
• T004 Add PrismaServer definition (depends on T002, T003)
• T005 Add PrismaServer to LSP_SERVERS array (depends on T004)
• T006 Export PrismaServer from index.ts (depends on T004)
• T007 Add unit tests for PrismaServer (depends on T004)
• T008 Update CLAUDE.md documentation (depends on T004)

References

• Prisma Language Tools
• Spec: specs/002-prisma-lsp/spec.md