feat(06-06): the D-10 locked-follow guidance camera + the context-aware BackButton resolver (GREEN)

- guidance/camera.ts: GUIDANCE_CAMERA_PADDING {320,64,64,64} / ZOOM 16 /
  EASE_MS 400 / PITCH 35; easeToSnapped rides the follow controller (ONE
  easing discipline) and never passes bearing — north-up, recorded call;
  onRerouteApplied is the documented camera no-op (setData lives in the
  route layer)
- map/follow.ts: follow(point, opts?) pose overrides spread over the
  Phase 3/5 defaults — no-opts calls stay byte-identical (RS13); the
  re-lock announces the mode (the recenter notch's return signal, RS12);
  the originalEvent unlock law untouched
- telegram/backbutton.ts: BackAction resolver ({hidden|close|callback})
  consulted per click + wire.sync() visibility re-apply (visible iff
  actionable); the legacy (hasOverlay, walkBack) shape composes internally
  so Phase 5 call sites and RS7 stay valid; close() only at the true root

web/src/map/follow.ts

@@ -7,6 +7,12 @@
  * Micro-Behaviors). A USER gesture (movestart carrying originalEvent) flips
  * to free — a programmatic move never does (T-03-16: the fix update must
  * never read as the user having panned).
+ *
+ * Phase 6 (D-10): follow() takes optional pose overrides so the guidance
+ * camera rides the SAME easing discipline and the SAME unlock law with the
+ * guidance pose (padding {320,64,64,64}, pitch 35, zoom 16, 400ms — the
+ * constants live in ../guidance/camera.ts). Absent fields fall back to the
+ * Phase 3/5 defaults — existing callers stay byte-identical (RS13).
  */
 import type { Map as MapLibreMap } from "maplibre-gl";
 import type { Fix } from "../location/types.ts";
@@ -16,6 +22,16 @@ export const RECENTER_DURATION_MS = 400;
 
 export type FollowMode = "following" | "free";
 
+/** Optional camera-pose overrides (D-10's guidance pose rides these).
+ *  Padding accepts MapLibre's number | per-edge form; pitch/zoom are only
+ *  passed when provided (the no-opts call keeps its exact key set). */
+export interface FollowOptions {
+  padding?: number | { top: number; bottom: number; left: number; right: number };
+  pitch?: number;
+  zoom?: number;
+  durationMs?: number;
+}
+
 export function createFollowController(map: MapLibreMap, onModeChange: (m: FollowMode) => void) {
   let mode: FollowMode = "following";
   let lock = false;
@@ -33,10 +49,17 @@ export function createFollowController(map: MapLibreMap, onModeChange: (m: Follo
     get mode(): FollowMode {
       return mode;
     },
-    follow(fix: Fix): void {
+    follow(point: Fix | { lat: number; lng: number }, opts: FollowOptions = {}): void {
       lock = true;
-      map.flyTo({ center: [fix.lng, fix.lat], padding: CAMERA_PADDING_PX, duration: RECENTER_DURATION_MS });
-      set("following");
+      map.flyTo({
+        center: [point.lng, point.lat],
+        padding: opts.padding ?? CAMERA_PADDING_PX,
+        duration: opts.durationMs ?? RECENTER_DURATION_MS,
+        ...(opts.pitch !== undefined ? { pitch: opts.pitch } : {}),
+        ...(opts.zoom !== undefined ? { zoom: opts.zoom } : {}),
+      });
+      mode = "following";
+      onModeChange(mode); // the re-lock is announced (the recenter notch's return signal)
       lock = false;
     },
   };