Release converge: fail fast on terminal resource failures instead of burning the deploy timeout

[ashishmax31]

Summary

The hub's converge reconciler (pkg/worker/release/converge.go in Stackdome/stackdome) has no fail-fast path. A release that can never converge sits until the deploy timeout expires (EffectiveSettings().DeployTimeoutMinutes, default 15m) and then fails with the generic message:

timed out waiting for convergence after 15m0s

Two agent-reported states are already terminal per revision and can be recognised immediately:

1. Build failure — agent sets Stalled=True with reason BuildFailed. The imagebuild controller already records the real failure on the release timeline; the release itself still waits out the clock.
2. Port readiness failure (new in v0.6.8-alpha, StackResource port readiness gate + branded Traefik error pages #52) — once a declared port outlives the 3-minute port-check grace window, the agent condemns the revision: WorkloadAvailable=False and Converged=False, both with reason PortNotListening, plus a readiness_failure entry in status.lastFailureDetail. Condemnation is terminal for that revision — the verdict is cached and never re-dialled until a new rollout. Nothing about waiting longer changes the outcome.

In both cases the release should be marked failed as soon as the terminal signal is observed, carrying the agent's reason/message instead of the generic timeout text.

Scope note

This is hub-side work — the agent already reports everything needed. Filed here alongside the port-readiness feature it follows from; transfer to Stackdome/stackdome if that fits the backlog better.

Not in scope

Surfacing the readiness failure on the release timeline (typed readiness_failure mapping + resource_failed event) is being done separately as part of the v0.6.8-alpha integration. This issue is only about ending the release early rather than waiting for the timeout.

Priority

P2 — degrades deploy DX (15 minutes of dead waiting on a diagnosable failure), no correctness impact; the timeline already names the cause. Estimate: ~2-3 hrs.