Increase max requests when using copilot on rails flow

[nturinski]

When running the Copilot on Rails scaffold flow, a low chat.agent.maxRequests limit causes Copilot to pause partway through with a "continue to iterate?" prompt. This PR raises that limit to a high ceiling at the Workspace scope so scaffolding can run uninterrupted — for both autopilot and guided runs.

Changes
Autopilot (autopilot.ts): replaced the temporary global maxRequests override (saved/restored) with a persistent Workspace bump (WORKSPACE_MAX_REQUESTS = 9999) that is intentionally not restored. Added getEffectiveMaxRequests() and raiseWorkspaceMaxRequests() helpers (no-op when no workspace folder is open or the limit is already high enough). The global chat.tools.global.autoApprove toggle is still saved and restored as before.
Guided scaffold (ScaffoldPlanViewController.ts): when the effective limit is below 1000, shows a Yes/No modal asking whether to raise the request limit for the workspace before launching the scaffold chat. "Yes" raises it; "No" (the modal's close affordance) proceeds unchanged. Skipped for autopilot (which already bumps it) and for the debug plan.
Notes
The workspace setting is written to settings.json and left in place by design.
chat.tools.global.autoApprove remains global and is always restored after an autopilot run.

[MicroFish91]

LGTM, although some of the explaining comments are long and repeated in multiple sections, so might be worth trimming/consolidating those

[nturinski]

@copilot Remove some of the comments that are extra verbose and don't explain critical code paths

[Copilot]

@copilot Remove some of the comments that are extra verbose and don't explain critical code paths

Done in 4d07240. I trimmed/rem oved the extra verbose comments and consolidated docs in autopilot.ts, ScaffoldPlanViewController.ts, and settingUtils.ts while keeping behavior unchanged.