Add floatingCardToolBarItems: card-attached floating views with alignment

[nighthawk]

What

Adds a card-attached floating-views affordance to TGCardViewController.

• TGCard.floatingCardToolBarItems: [UIView]? — views floated at the bottom of the card itself (not over the map, unlike top/bottomMapToolBarItems). They're hosted in a stack added to the controller's view, pinned to the bottom of the card's visible area at .defaultHigh priority but clamped to the safe area as a required constraint — so they prefer the card's bottom edge yet never drop below the screen when the card is collapsed/peeking and its content extends past the bottom.
• TGCard.floatingCardToolBarAlignment (.leading / .center / .trailing / .fill, default .center) — horizontal placement within the card. .center suits a status pill; .leading/.trailing a FAB-style primary action; .fill a full-width button. The leading/trailing inequality clamps stay active for every alignment, so a wide row never overflows the card.

Why

There was no way to float a control that stays attached to the card and remains visible regardless of the card's drag position — top/bottomMapToolBarItems overlay the map. The immediate consumer is TripGo's agenda "recalculating…" status pill, which needs to stay visible at any card position; the alignment option also opens the door to a trailing FAB-style primary action.

Notes for reviewers

• didBuild timing: card-attached items are also (re)populated right after didBuild, not only during the push/pop floating-view refresh. Cards commonly configure their toolbar items in didBuild, which runs after that refresh, so items set there would otherwise be silently dropped. Population is idempotent (populateFloatingView cleans up first), and the items are persistent views owned by the card, so they survive a re-populate.
• Scope: purely additive — no change to existing public API or to top/bottomMapToolBarItems. Covered presentation paths: initial/root present, push, pop. TGPageCard children setting these in didBuild aren't forwarded (separate flow) — out of scope.
• Builds clean standalone (iOS Simulator).

🤖 Generated with Claude Code

[nighthawk]

Suggested squash-merge commit message:

feat: add floatingCardToolBarItems — card-attached floating views with alignment

Float controls attached to the card (not the map) that stay visible at any
card drag position: pinned to the card's bottom edge but clamped to the safe
area. `floatingCardToolBarAlignment` (.leading/.center/.trailing/.fill,
default .center) controls horizontal placement — a centred status pill, a
trailing FAB-style action, or a full-width button. Card-attached items are
(re)populated after `didBuild` too, so items configured there aren't dropped.
Purely additive — no change to existing public API.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

After merge: tag a new version in [2.4.4, 3.0.0) (current TripGo pin is 2.4.3) so TripGo can bump its package pin and consume floatingCardToolBarItems.