chore: add timeout for log following of an unresponsive run

[socksy]

This kept hanging when running the tests with a broken runner, and IMO timing out with an explicit error is better than hanging forever.

Summary by CodeRabbit

• Bug Fixes
  • Improved run start handling with a 30-second timeout limit. The application will no longer hang indefinitely while waiting for a run to start. If a runner fails to respond within the timeout window, a clear error message is displayed indicating potential runner unavailability.

[coderabbitai]

📝 Walkthrough

Walkthrough

The changes introduce a 30-second timeout mechanism for waiting for a run to start across multiple modules. When the timeout expires, the system either logs an error and aborts the wait or returns a new RunStartTimeout error variant, replacing unbounded polling with bounded, time-limited waiting.

Changes

Cohort / File(s)	Summary
Timeout error variant crates/tower-cmd/src/error.rs	Added RunStartTimeout variant to the public Error enum with a message indicating timeout while waiting for run to start and potential runner unavailability.
Timeout implementation crates/tower-cmd/src/run.rs, crates/tower-cmd/src/apps.rs	Introduced RUN_START_TIMEOUT constant (30 seconds) and wrapped polling loops with timeout guards; on timeout, either returns RunStartTimeout error or logs error and aborts wait; preserves early return on successful start detection.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~12 minutes

Poem

A rabbit with a stopwatch bright, 🐰⏱️
Counts thirty seconds, left and right,
No endless waits forevermore,
The runner's ready, that's what's for! ✨

🚥 Pre-merge checks | ✅ 2 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 66.67% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (2 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately summarizes the main change: adding a timeout mechanism for log following when a run becomes unresponsive.

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✨ Finishing touches

• 📝 Generate docstrings

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment
• Commit unit tests in branch add-timeout-to-log-following

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No actionable comments were generated in the recent review. 🎉

🧹 Recent nitpick comments

crates/tower-cmd/src/apps.rs (1)

270-273: Keep timeout messaging consistent with the shared error variant.

Reusing Error::RunStartTimeout avoids message drift between run and apps logs flows.

♻️ Suggested tweak for consistent messaging

-use crate::{api, output};
+use crate::{api, output, Error};
@@
-                    output::error("Timed out waiting for run to start. The runner may be unavailable.");
+                    output::error(&Error::RunStartTimeout.to_string());

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