feat(fctx-migration): implement context migration and linking

[oswaldo]

This PR implements the Context Migration & Linking feature (009-fctx-migration).

Summary

• Global Config: Implements GlobalConfig to track context locations in ~/.first/first.conf.
• Save to Custom Path: Adds save --to <path> to save contexts to any location.
• Link Mode: Adds save --link and update --link to replace source files with symlinks to the artifacts.
• Move Command: Adds mv command to move contexts and automatically update symlinks.
• Symlink Manager: Implements safe symlink handling.

Verification

• Automated tests added for all new components.
• Manual verification script specs/009-fctx-migration/verify_manual.sh passes.
• Walkthrough updated.

[Copilot]

Pull request overview

This PR implements the Context Migration & Linking feature, enabling users to save contexts to custom locations, create symlinks to artifacts, and move contexts while automatically updating references. The implementation adds a global configuration registry (~/.first/first.conf) to track context locations outside standard project directories.

Key changes include:

• Global Configuration: GlobalConfig manages a central registry of context locations
• Custom Save Location: save --to <path> allows saving contexts anywhere on the filesystem
• Linking Support: save --link and update --link replace source files with symlinks to artifacts
• Context Migration: mv command moves contexts and updates all workspace symlinks

Reviewed changes

Copilot reviewed 35 out of 35 changed files in this pull request and generated 8 comments.

Show a summary per file

File	Description
src/main/scala/first/config/GlobalConfig.scala	Implements central registry for tracking context locations
src/main/scala/first/config/ConfigWriter.scala	Provides HOCON writing utilities for configuration files
src/main/scala/first/config/ConfigReader.scala	Enhanced to discover contexts from GlobalConfig registry
src/main/scala/first/core/SymlinkManager.scala	Handles safe symlink creation with OS-specific warnings
src/main/scala/first/core/Mv.scala	Implements context moving with symlink updating logic
src/main/scala/first/core/Save.scala	Extended to support custom paths and linking mode
src/main/scala/first/core/Update.scala	Extended to support linking mode for added artifacts
src/main/scala/first/cli/MvCommand.scala	CLI interface for mv command
src/main/scala/first/cli/SaveCommand.scala	Extended with --to and --link options
src/main/scala/first/cli/UpdateCommand.scala	Extended with --link option
test_output.txt	Test execution results (should not be in version control)
specs/009-fctx-migration/*	Complete feature specification and documentation

Comments suppressed due to low confidence (1)

src/test/scala/first/core/UpdateTests.scala:1

• The test 'Update works for custom location context' is failing. The test expects the artifact to be created at customDir / 'artifacts' / 'custom.txt', but the assertion fails. This indicates the Update command may not be properly resolving custom context locations from GlobalConfig. Review the Update.run implementation to ensure it correctly handles contexts registered in GlobalConfig.

package first.core

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[Copilot]

Pull request overview

Copilot reviewed 38 out of 38 changed files in this pull request and generated 6 comments.

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