revert: drop wire segment caps that silently truncated geometry

Remove MAX_SEGS_PER_WIRE = 100_000 and MAX_TOTAL_SEGS = 3_000_000.
These were stop-gap GPU-memory guards that mutated visible output:
single complex entities were cut mid-geometry, and entire wires past
the 3M total were dropped by arrival order with no spatial awareness.
Either is worse than honestly drawing whatever the file contains —
truncated arcs and missing road segments look like bugs to the user,
not "we ran out of GPU memory."

The matching "Temporary Workarounds" section in
RENDERING_OPTIMIZATION.md goes with them. Per-entity LOD and
viewport culling (Phase 1 + 3.2 in the same doc) remain the right
long-term answer; until they land, prefer correctness over a soft
crash on pathological files.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

RENDERING_OPTIMIZATION.md

@@ -12,50 +12,6 @@ Current pipeline order:
 
 ---
 
-## Temporary Workarounds (to be reverted)
-
-> **These are stop-gap measures to prevent crashes on large files. They must be removed
-> once the proper Phase 1–3 optimizations are in place, because they silently drop geometry
-> rather than culling it intelligently.**
-
-### Wire Segment Hard Caps (commit 321433e)
-
-**Problem:** Some entities — particularly dense `PolyfaceMesh` / `PolygonMesh` edge meshes,
-high-resolution splines, or very large polylines — tessellate into hundreds of thousands of
-line segments. Each segment expands to 6 GPU vertices × 96 bytes = 576 bytes. A single
-pathological entity could allocate hundreds of megabytes; a large file with many such entities
-exhausts all available GPU memory and crashes the renderer.
-
-**Temporary fix applied in `src/scene/pipeline/wire_gpu.rs` and `src/scene/pipeline/mod.rs`:**
-
-1. **Per-entity cap — `MAX_SEGS_PER_WIRE = 100_000`**
-   Defined as a `pub const` in `wire_gpu.rs`. Applied in both `WireGpu::build()` (used by
-   `WireGpu::new`) and `WireGpu::from_batch()`. If a single `WireModel` contains more than
-   100 K segments, the excess tail is silently truncated and a warning is printed to stderr:
-   ```
-   [H7CAD] wire '<handle>': <N> segments exceeds limit (100000), truncating
-   ```
-
-2. **Scene-level budget — `MAX_TOTAL_SEGS = 3_000_000`**
-   Enforced in `Pipeline::upload_wires()`. Wires are processed in the order they arrive; once
-   the running segment total would exceed 3 M, all remaining wires are skipped for that frame:
-   ```
-   [H7CAD] upload_wires: skipped <N> wire(s) — total segment budget (3000000) exceeded
-   ```
-   At 576 bytes/segment the budget caps GPU wire memory at roughly **1.6 GB**.
-
-**Why this must be reverted:**
-- Truncation cuts an entity mid-geometry; the rendered result is visually wrong.
-- Skipping by arrival order is arbitrary — important visible entities may be dropped while
-  invisible off-screen entities are retained (no spatial awareness).
-- The correct solution is Phase 1 (AABB cull before upload) + Phase 3.2 (adaptive arc segments),
-  which eliminate the excess geometry without ever creating it in the first place.
-
-**Revert when:** Phase 1.3 (CPU cull before upload) is landed and verified to keep peak GPU
-wire memory below ~512 MB for the pathological files that triggered these caps.
-
----
-
 ## Phase 1 — Viewport Bounding-Box Culling
 
 **Goal:** Skip CPU upload and draw calls for entities outside the camera view.