Add Pi TUI daemon launcher

[glittercowboy]

Summary

• Adds gsd-cloud pi-tui for launching Pi TUI with the daemon Pi extension, provider registry, model cycling list, session path, runtime prompt, and task-scoped tool environment.
• Adds scripts/pi-tui.sh as the local entrypoint for running the launcher from a daemon checkout.
• Exposes shared Pi argument and environment builders from internal/pi so the TUI launcher uses the same daemon configuration path.

Verification

• go test ./...
• go build ./...
• bash -n scripts/pi-tui.sh
• scripts/pi-tui.sh --help
• scripts/pi-tui.sh --print-command --cwd . --session-id smoke --provider codex-appserver --model gpt-5.5 "say hi"

Summary by CodeRabbit

• New Features

  • Added pi-tui CLI command supporting configurable working directory, provider/model selection, session management, custom instructions, skill files, agent tools, and browser grant settings.

• Chores

  • Added shell script entrypoint for the pi-tui command.
  • Exposed internal helper functions for command argument and environment processing.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro Plus

Run ID: 120507b4-35d3-47bf-94e8-38bb48b00a00

📥 Commits

Reviewing files that changed from the base of the PR and between 0cd28a2 and 43690bc.

📒 Files selected for processing (3)

• cmd/pi_tui.go
• internal/pi/executor.go
• scripts/pi-tui.sh

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📝 Walkthrough

Walkthrough

This pull request introduces a new pi-tui CLI command that orchestrates the Pi TUI process startup, handling extension resolution, flag parsing, custom instructions concatenation, session file management, optional agent-tools backend initialization, and process lifecycle management. Two utility functions in the executor package are also exposed for external use.

Changes

Cohort / File(s)	Summary
Pi TUI Command cmd/pi_tui.go, scripts/pi-tui.sh	New Pi TUI command implementation with comprehensive flag parsing (cwd, provider, models, session settings, custom instructions, skill files, agent tools), extension path resolution with fallback chain, session file determination under ~/.gsd-cloud/pi-sessions/, optional agent-terminal backend startup, and process execution with context-aware termination handling.
Executor Helpers internal/pi/executor.go	Exports two new public functions, ProcessArgs and ProcessEnv, that wrap existing internal argument and environment variable construction logic for Pi daemon configuration.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~30 minutes

Possibly related PRs

• Append custom task instructions in Pi executor #80: Introduces CustomInstructions option that directly integrates with the newly exposed ProcessArgs and ProcessEnv functions to construct Pi daemon configuration.
• Persist Pi sessions by GSD session ID #52: Implements Pi session persistence behavior using ~/.gsd-cloud/pi-sessions/<safe>.jsonl, which is directly used by the new pi-tui command for session management.
• Enable Pi skill discovery #77: Modifies Pi daemon command-line argument construction to enable skill discovery, affecting the same argument-building logic exposed by this PR's new functions.

Poem

🐰 A terminal for Pi, now we can run,
With extensions resolved and custom instructions spun,
Agent tools dancing, sessions secure,
The rabbit hops forward, of changes quite sure! ✨

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 8.70% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The pull request title 'Add Pi TUI daemon launcher' clearly and accurately summarizes the main change—introducing a new CLI command and supporting infrastructure to launch the Pi TUI via the daemon.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch codex/pi-tui-launcher

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