Apply the run configuration on run, and add a "Run Target with Parameters…" command

[ChrisonSimtian]

Wire the saved run configuration into the two ways a target gets run.

Implemented on feature/views-and-run-config (#2) — src/extension.ts.

Two modes

Action	Behaviour
▶ inline (fallout.runTarget)	Runs silently with the saved configuration applied — parameters appended as args, secrets injected as env.
Run Target with Parameters… (fallout.runTargetWithParameters)	Opens an InputBox prefilled with <target> <saved args> so you can tweak before running. Secrets still apply as env; cancelling runs nothing.

The prefill matters: it makes the saved configuration visible and editable at the moment of use, rather than something you have to remember you configured.

Notes

• Workspace root falls back to the first workspace folder when no build graph has been located yet, so running works before a graph exists.
• Cancelling the InputBox (undefined) is distinguished from submitting an empty string.

Depends on #12 and #13 for the store.

Acceptance

• ▶ applies saved parameters and secrets without prompting
• The prompt is prefilled with target plus saved args, and edits are respected
• Cancelling the prompt runs nothing