fix(camera): frame the city on initial load to match R (#62)

[thalida]

Closes #62.

Problem

The first auto-frame on world load was off (city not centered/fit); pressing r re-framed it correctly. Root cause: the initial frame was captured from a transient early state, while r re-captures later once everything has settled.

Three framing inputs differed between the auto-frame and r (each confirmed via instrumentation — rootW 32→96, tallestH null→1024, labelHalfW 128→512). The first two are the empty boot / placeholder-height skeleton vs the settled real city; the third is the web font loading.

Fix

Every camera-framing input now comes from layout data / settings / pure math, and the camera re-snaps through the load's applies:

1. Tallest building height — buildings.getTallest() looped the building cell meshes, which build asynchronously, so it was null at frame time and only valid by the time r ran. Replaced with a cityState.tallestBuilding computed derived from layout.buildings (already includes the worker's media-silhouette sizing). It tracks layout (reassigned every apply), so the height is fresh on the skeleton→final reuse apply where placeholder heights become real without bumping structureRevision. The rig reads it from cityState; the now-dead buildings.getTallest is removed.

2. The final manifest applies as a REUSE (same tree_signature → structureRevision and bbox frozen), so the old bbox-tracking reframe never re-fired and the camera stayed on the early framing (empty boot, then skeleton placeholder heights). The composer now follows the framing on every apply (cityRevision) until the user first takes control (OrbitControls start), so it tracks the world settling but never yanks a user-set view. reset() also recomputes from current state instead of a cached pose, removing an effect-ordering hazard.

3. Repo-label width — the height-fit sampled the label's left/right corners, so the label's world width (from the text-texture aspect, which only settles once the Orbitron web font loads) pulled the camera back and shifted the frame after load. The label is centered on the gem and already sits inside the width-fit frame, so the fit now uses only the label's top-edge height, not its width — removing the last rendered/font dependency from framing.

Tests

• cityState.tallestBuilding unit tests, incl. the reuse-apply-without-structureRevision case (the crux).
• initialFraming integration tests: re-snaps on a post-load layout rebuild before the user interacts; stops following once the user takes control.
• cameraRig test locking in that the repo-label width does not affect start framing (only its top-edge height).
• Full suite green (2304), typecheck / eslint / prettier clean.

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