fix(gitinfo): pick workflow-dispatch inputs and stop command-goroutine crashes

[jongio]

Summary

Two changes to GitHub Actions workflow dispatch in the GitHub panel:

1. Parameter picker — dispatch now prompts for each declared workflow_dispatch input in turn, instead of one free-form key=value blob:

   • choice inputs → an action picker of the valid options, preselected on the workflow's default
   • boolean inputs → a true/false picker, preselected on the default
   • free-form inputs (string/environment/unspecified) → a text field pre-filled with the default; accepts a custom value
   • a workflow with no inputs dispatches immediately; if the workflow YAML can't be read, the free-form composer is offered as a fallback

2. Crash fix (root cause) — dispatching could still kill the whole TUI (program experienced a panic, empty crashes dir), even after fix(tui): capture panics and harden GitHub workflow dispatch #362 added crashlog.GuardTUI. GuardTUI only guards the model's Init/Update/View on the main goroutine; a panic inside a tea.Cmd goroutine (run by Bubble Tea's execBatchMsg) becomes a fatal ErrProgramPanic that no report captures. Historical bubbletea-panic-*.log stacks pinpointed nil-client derefs in the GitHub loaders running in those goroutines.

   • New crashlog.CaptureCmdPanic (a quiet crash-report writer — no stderr, since the TUI owns the terminal) + gitinfo.guardedGitHubCmd, wrapping every GitHub data loader and the dispatch closures so a panic becomes a crash report + error toast instead of a crash. A recovered panic also clears any stranded Loading… state.

Also fixed (found along the way)

• Seven GitHub command functions (cancel run, merge PR, comment, request reviewers, close/reopen issue, create PR, assign self) still dereferenced a nil client in their goroutine — now guarded with a clear error toast.
• crashlog.Write is now serialised (mutex) with collision-free filenames (atomic sequence); previously same-second reports could overwrite/corrupt each other once CaptureCmdPanic made writes concurrent and repeatable.

Testing

• Full go test ./... — pass (pre- and post-rebase)
• go vet ./..., golangci-lint ./... (0 issues), gofumpt -l . (clean), deadcode ./... (0 new), govulncheck ./... (no vulnerabilities)
• New tests cover the choice/boolean/text/no-input/fallback paths, empty-value-keeps-default, the panic safety net + stranded-loading recovery, concurrent crash-report distinctness, and the nil-client guards. Coverage: gitinfo 81.6%, notify 89.4%, crashlog 87.5%.

Design + test plan: docs/specs/workflow-dispatch-param-picker/.

Follow-up to #362.