Add function support

[fredvisser]

Added (new files/features):

• function CLI subsystem: function_click.py (full manage + execute + init commands for unified /nifunction/v2 service).
• Secure template bootstrap helper: function_templates.py.
• Config support: config.py plus .env.example for local dev overrides.
• Comprehensive function command tests: test_function_click.py.

Modified:

• README.md: Large new “Function Management” section, usage examples, dev env notes, added function-related feature bullets.
• _version.py: Version bump.
• main.py: Registers new function command group.
• .gitignore: Added entry for .env

Scale of change:

• ~2500 insertions, 4 deletions.
• Major new functionality (WASM function definition & execution management, template init).
• No broad refactors to existing non-function modules besides wiring/version/docs.

Key capabilities introduced:

• List/query/get/create/update/delete function definitions (paginated, filters, workspace mapping).
• Synchronous execute with HTTP-style parameters (method/path/headers/body) and guarded default (GET /) fallback only when user supplies none.
• Interface summary (default path + endpoints) in get output.
• Function executions list/get/cancel/retry support (unified model).
• Template init command with secure GitHub tarball download (TypeScript & Python examples), --force overwrite semantics, path traversal & symlink guards.
• Environment-based service URL overrides via .env.

Test coverage additions:

• Pagination aggregation, get, execute parameter wrapping, interface summary, template init (success + non-empty dir abort).

[Copilot]

Pull Request Overview

This PR adds comprehensive function management capabilities to slcli, introducing WebAssembly (WASM) function definition and execution management through a unified v2 API. The implementation includes template initialization, secure GitHub template downloads, and configuration support.

Key changes:

• New function CLI subsystem with complete CRUD operations for function definitions and execution management
• Template bootstrap system with secure GitHub tarball downloads and path traversal protection
• Environment-based configuration support via .env files
• Comprehensive test coverage for all new functionality

Reviewed Changes

Copilot reviewed 8 out of 9 changed files in this pull request and generated 13 comments.

Show a summary per file

File	Description
tests/unit/test_function_click.py	Comprehensive test suite for function CLI commands including pagination, execution, and template initialization
slcli/main.py	Registers new function command group and updates docstring format
slcli/function_templates.py	Secure template download helper with safety checks against path traversal and symlinks
slcli/function_click.py	Complete function CLI implementation with manage/execute command groups and unified v2 API integration
slcli/config.py	Configuration management for function service URLs
slcli/_version.py	Version bump with comment update
README.md	Extensive documentation for function management features and usage examples
.env.example	Example environment configuration file