feat: Replace fixed-width box output with status spine format

[konard]

Summary

This PR replaces the fixed-width box output format with a new "status spine" format that is:

• Width-independent: No truncation, no jagged boxes
• Lossless: All data visible and copy-pasteable
• Portable: Works in TTY, tmux, SSH, CI, and log files
• Clear: Visual distinction between metadata (│), command ($), and program output (no prefix)

Before (box format - REMOVED)

╭────────────────────────────────────────────────────────╮
│ Session ID: abc-123-def-456-ghi                        │
│ Starting at 2025-01-01 00:00:00: echo hello            │
│ [Isolation] Environment: docker, Mode: attached        │
╰────────────────────────────────────────────────────────╯

After (status spine format - ONLY FORMAT)

│ session   abc-123-def-456-ghi
│ start     2025-01-01 00:00:00
│
│ isolation docker
│ mode      attached
│ image     ubuntu:latest
│ container docker-123
│
$ echo hello

hello world

✓
│ finish    2025-01-01 00:00:01
│ duration  0.500s
│ exit      0
│
│ isolation docker
│ mode      attached
│ image     ubuntu:latest
│ container docker-123
│
│ log       /tmp/start-command-123456.log
│ session   abc-123-def-456-ghi

Key Changes

JavaScript

• Updated js/src/lib/output-blocks.js with spine format functions only:
  • createSpineLine() - Creates metadata lines with │ prefix
  • createEmptySpineLine() - Creates empty spine separator
  • createCommandLine() - Creates command line with $ prefix
  • getResultMarker() - Returns ✓ or ✗ based on exit code
  • parseIsolationMetadata() - Parses isolation info from extraLines
  • generateIsolationLines() - Generates spine-formatted isolation metadata
• Removed all legacy BOX_STYLES, getBoxStyle(), and related box-drawing functions
• Updated createStartBlock() and createFinishBlock() to use spine format
• Updated formatDuration() to append 's' suffix (e.g., "0.500s")

Rust

• Updated rust/src/lib/output_blocks.rs with equivalent spine format functions
• Added IsolationMetadata struct for parsed metadata
• Removed all legacy BoxStyle, get_box_style(), and box-drawing functions
• Updated both block functions to use new format

Tests

• Updated js/test/output-blocks.test.js with tests for spine format only
• Updated js/test/echo-integration.test.js to verify spine format only (no backward compat)
• Updated js/test/ssh-integration.test.js to verify spine format only
• Updated rust/tests/output_blocks_test.rs with equivalent Rust tests
• All tests pass for both JavaScript and Rust

CI/CD Improvements

• Install screen and tmux in GitHub Actions for Linux and macOS
• Added explicit integration tests for screen, tmux, and docker isolation modes
• Rust build job now only runs on push to main, not on PRs (tests already verify builds)

Test Plan

• Run bun test - All JS tests pass
• Run cargo test - All Rust tests pass
• Run bun run lint - Linting passes
• Run cargo clippy - No warnings
• Run cargo fmt --check - Formatting passes
• CI includes screen/tmux/docker isolation tests

Closes #64

🤖 Generated with Claude Code

[konard]

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[konard]

We can install screen, tmux, docker in GitHub Actions (if not installed already) and make sure we do really test them all. It is cheap, and will make sure our CLI tool will work the same way on all platforms.

Also make sure we do drop support for previous bordered fixed width blocks like at all. We should support only new output format with spine | and $ and ✓ and ✗.

Ensure all changes are correct, consistent and fully meet the requirements in both JS and Rust versions.

Also, do we really need to execute https://github.com/link-foundation/start/actions/runs/20801811382/job/59748219113?pr=65 for pull requests? Are tests not enough for rust? May be we should update our CI/CD?

[konard]

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[konard]

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[konard]

All tests on all platforms should pass. Find root causes and fix them all.

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[konard]

Looks like we need to update our changeset check for Rust at: https://github.com/link-foundation/start/actions/runs/20802747294/job/59750799581?pr=65

At the moment it didn't check for absense of changeset and just passed it should be fixed.

If https://github.com/link-foundation/rust-ai-driven-development-pipeline-template has the same issue file issue there.

[konard]

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[konard]

🤖 Solution Draft Log

Summary of changes in this session:

1. Added Rust changelog fragment () for the spine format changes

2. Fixed Rust changelog check validation - The previous check incorrectly passed when ANY changelog fragments existed in the directory, even if none were added in the current PR. Now it properly validates that a changelog fragment was added in the PR diff itself.

3. Filed issue in template repo - Created link-foundation/rust-ai-driven-development-pipeline-template#13 to report the same changelog check bug there.

Verification:

• ✅ All local tests pass (JS and Rust)
• ✅ Linting passes for both JS and Rust
• ✅ Legacy box format completely removed from JS and Rust
• ✅ Spine format implemented consistently in both JS and Rust
• ✅ All CI checks passing on all platforms

Changes confirmed:

• Box-drawn UI removed
• Status spine format with │ prefix for metadata, $ for command
• Result markers ✓ and ✗ for success/failure
• Isolation metadata repeated in footer
• log and session always last in footer
• screen/tmux/docker isolation tests added to CI

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[konard]

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