feat: add ProgressIndicatorStyle.PILL for multi-step progress indicators

[paul-at-equal]

Summary

• Adds ProgressIndicatorStyle (DOTS default / PILL) so the current step in a multi-step tooltip's progress indicator can render as an elongated pill instead of a same-size dot — an iOS-style page indicator look, requested to match a reference onboarding screen.
• New CoachmarkConfig.progressIndicatorStyle and CoachmarkConfig.progressActivePillWidth (default 20.dp) control it. No new color config needed — reuses existing CoachmarkColors.progressActiveColor / progressInactiveColor.
• DOTS behavior is unchanged (steps up to and including the current one fill in, matching current default behavior exactly).
• PILL highlights only the current step; every other step (before or after) stays a plain dot.
• Added a "Start Tour (Pill)" button to the Multi-Step Sequence sample so both styles are easy to compare side by side.
• Bumped to 1.0.0-beta16 and updated CHANGELOG.md.

This is independent of #51 (the TEARDROP connector PR) — branched from main directly so it can be reviewed/merged on its own.

Test plan

• ./gradlew :lumen:compileDebugKotlinAndroid :lumen:compileKotlinJvm :lumen:compileKotlinIosArm64 :lumen:compileKotlinIosSimulatorArm64 :lumen:compileKotlinIosX64 :sample:compileDebugKotlinAndroid — all targets compile
• ./gradlew :lumen:apiDump / :lumen:apiCheck — API dumps regenerated and verified
• ./gradlew :lumen:testDebugUnitTest :lumen:jvmTest — full suite green, including a new Roborazzi golden (tooltip_multiStep_pillIndicator.png) and a new ProgressIndicatorStyle.entries unit test
• Visually confirmed the recorded screenshot matches the requested reference (pill on the current step, small dots elsewhere)

🤖 Generated with Claude Code

[aldefy]

Closing as superseded — ProgressIndicatorStyle.PILL merged to main via #53, cherry-picked with your authorship intact (commit 145e9ed, feat: add ProgressIndicatorStyle.PILL for multi-step progress indicators).

Context: reviewing this alongside #51 against the actual design driving both showed a pattern of new visual requirements landing as new enum cases + config fields in :lumen for things that are really app-specific. #53 adds three general extension points (progressIndicator composable slot, customConnector lambda, CutoutShape.Custom) so future asks like this don't need a library change at all — but PILL specifically is common enough (iOS-style page indicator) that it was worth keeping as a built-in convenience on top of the slot, rather than only leaving it as an app-side example. So this PR's actual feature shipped as-is, just via #53's branch instead of this one.

Thanks for building it — no rework needed on your end.