fix(ui): clamp generation progress percentages

[akkupratap323]

What changed

GenerationProgress could display percentages above 100% when a job reported more completed pages than its stale total. For 241 / 5, the UI rendered 4820%, passed an invalid value to Radix, dropped aria-valuenow, and generated malformed transform CSS.

This change clamps the displayed generation percentage to 0-100. It also hardens the shared Progress primitive so all finite inputs are bounded before reaching Radix or the indicator transform; non-finite inputs retain the indeterminate state.

Validation

• Focused generation and progress tests: 21 passed
• Shared UI TypeScript check: passed
• Shared-package import boundary check: passed
• Full shared UI suite: 1,658 passed; two unrelated system-map suites could not load a user-level PostCSS plugin, and two existing heavy UI tests timed out on this Windows machine
• Regression tests were run before implementation: 9 failed on overflow, negative, and non-finite inputs

Closes #2176

[akkupratap323]

@RaghavChamadiya The assigned fix is ready. Could you please review this PR and assign it if appropriate? Thank you.

[RaghavChamadiya]

Thanks @akkupratap323. Clamping at both the generation boundary and the shared progress component covers raw percentages as well as finite derived values, while preserving indeterminate handling for missing and non-finite input. The regression coverage matches those cases. Approved.