feat: add OMNISQL_PROJECT env var to support custom DB client project names

[zerafachris]

Summary

WorkspaceConfigParser hardcodes the DB client (DBeaver) project/workspace folder name to 'General' in 6 places. Any workspace that uses a custom or renamed project name (e.g. a real-world project literally named DataPlatform) returns zero connections from list_connections, with no way to configure it — OMNISQL_WORKSPACE only overrides the workspace root, not the project folder underneath it, and OMNISQL_CLI_PATH is unrelated (it only feeds the CLI query-execution fallback, not connection discovery).

I hit this directly: my real DBeaver project is named DataPlatform, containing 9 real connections across several folders. list_connections returned [] until I worked around it locally with a symlink (~/Library/DBeaverData/workspace6/General -> .../DataPlatform). This PR removes the need for that workaround.

Changes

• Add optional projectName?: string to WorkspaceConfig (src/types.ts)
• Add DEFAULT_PROJECT_NAME = 'General' constant in src/config-parser.ts; constructor now does config.projectName ?? DEFAULT_PROJECT_NAME
• Replace all 6 hardcoded 'General' literals in WorkspaceConfigParser with this.config.projectName!: detectNewFormat() (x2), getConnectionsFilePath(), getCredentialsFilePath(), parseConnections() fallback path, isWorkspaceValid()
• Wire new OMNISQL_PROJECT env var into the WorkspaceConfigParser instantiation in src/index.ts, and document it in the CLI --help text
• Add test coverage in tests/config-parser.test.ts (asserts default 'General' path vs. a custom projectName path via getDebugInfo())
• Document OMNISQL_PROJECT in README.md (env var table + "Workspace Format Support" section), docs-site/docs/getting-started/configuration.md, docs-site/docs/getting-started/installation.md, and examples/claude-desktop-config.json

Fully backward compatible — default behavior ('General') is unchanged when the new env var/config field is not set.

Related Issues

None filed — found and fixed while setting this MCP server up against a real workspace.

Checklist

• Tests pass locally (npm test — 45/45 passing, including 2 new projectName tests)
• Linting passes (npm run lint, npm run build — clean)
• Documentation updated (README, docs-site pages, Claude Desktop config example)
• Breaking changes documented (none — fully backward compatible, defaults preserve current 'General' behavior)