feat(photos): apply frozen mask to batch siblings after Calculate (#62)

After calibration Calculate, reuse approved sheet/sensitivity on non-calibration
photos via the mask worker + inventory compose. Persist per-photo ok/error on
measure.batchApply and the device draft for #64; leave Mask UI unopened and keep
scale/widths/sqft/bdft on the calibration results only.

frontend/src/capture/capture.types.ts

@@ -70,6 +70,13 @@ export interface Measures {
   sourceBelowFloor: boolean;
 }
 
+// Result of applying the calibration mask to one batch sibling. The
+// calibration slot is null because its inventory PNG lives in Measures.
+export type BatchPhotoResult =
+  | null
+  | { status: 'ok'; inventoryPng: Blob }
+  | { status: 'error'; message: string };
+
 // The machine. 'resume' exists only while a draft exists and has not been chosen.
 // M2: 'batch' + 'pickCalibration' replace M1 'addPhoto' — accumulate, then user picks calibration.
 export type Capture =
@@ -97,6 +104,8 @@ export type Capture =
       lengthEighths: Eighths;
       thicknessEighths: Eighths;
       results: Measures | null;
+      /** Capture-order sibling results from the post-Calculate batch pass. */
+      batchApply?: BatchPhotoResult[];
     };
 
 // Placeholder geometry for batch-only drafts (no mask yet).
@@ -131,6 +140,8 @@ export interface Draft {
   thicknessEighths: Eighths;
   results: Omit<Measures, 'inventoryPng'> | null; // present when results computed
   inventoryPng: Blob | null; // stored so Continue can show Measure results
+  /** Capture-order batch apply results; blobs are retained for the #64 lineup. */
+  batchApply?: BatchPhotoResult[];
 }
 
 // Worker protocol. Job ids increase; the worker drops anything older than the

frontend/src/capture/session.calibrate.test.ts

@@ -408,10 +408,15 @@ test('#61: Calculate produces inventory PNG + M1 measures for calibration source
     assert.equal(cap.source.widthPx, MASK_W, 'measure source dims from calibration decode');
   }
 
-  // Still only calibration blob through the mask worker.
+  // Pre-#62: Mask UI path used only the calibration blob. After Calculate, #62
-  for (const blob of FakeMaskWorker.inits) {
+  // may init the worker on non-calibration siblings for frozen-mask apply.
-    assert.equal(blob, b);
+  const preApplyInits = FakeMaskWorker.inits.filter((blob) => blob === b || blob === a);
-  }
+  assert.ok(preApplyInits.some((blob) => blob === b), 'calibration must have been masked');
+  // Sibling apply may touch `a`; that is #62, not a #61 regression of Mask UI.
+  assert.ok(
+    FakeMaskWorker.inits.filter((blob) => blob === b).length >= 1,
+    'calibration blob must appear in worker inits',
+  );
 
   s.dispose();
 });

frontend/src/capture/session.ts

@@ -1,6 +1,6 @@
 import { writable } from 'svelte/store';
 import type {
-  Capture, Draft, Eighths, Mask, MaskParams, Measures, Sheet, Source, WorkerIn, WorkerOut,
+  BatchPhotoResult, Capture, Draft, Eighths, Mask, MaskParams, Measures, Sheet, Source, WorkerIn, WorkerOut,
 } from './capture.types';
 import {
   DEFAULT_MASK_PARAMS, EMPTY_ABOX, EMPTY_BBOX, eighthsToIn,
@@ -8,7 +8,7 @@ import {
 import { loadDraft, saveDraft, clearDraft } from '../draft/idb';
 import { measure } from '../measure/measure';
 import { orientedRect } from '../geometry/rect';
-import { encodeInventoryPng } from '../png/inventory';
+import { encodeInventoryPng, type InventoryInput } from '../png/inventory';
 
 const DEBOUNCE_MS = 2000;
 const BUSY_MS = 300;
@@ -50,6 +50,8 @@ export interface CaptureSession {
 
 export interface SessionOpts {
   draft?: DraftStore;
+  /** Injectable only for deterministic tests; production uses encodeInventoryPng. */
+  encodeInventory?: (input: InventoryInput) => Promise<{ blob: Blob; sourceBelowFloor: boolean }>;
 }
 
 const defaultDraft: DraftStore = { loadDraft, saveDraft, clearDraft };
@@ -61,6 +63,7 @@ const batchPhotosOf = (d: Draft): Source[] =>
 // Every transition to an approved branch persists; no explicit "save".
 export function createCaptureSession(opts: SessionOpts = {}): CaptureSession {
   const drafts = opts.draft ?? defaultDraft;
+  const encodeInventory = opts.encodeInventory ?? encodeInventoryPng;
   const capture = writable<Capture>({ k: 'batch', photos: [] });
   const busy = writable(false);
   let state: Capture = { k: 'batch', photos: [] };
@@ -210,6 +213,7 @@ export function createCaptureSession(opts: SessionOpts = {}): CaptureSession {
         lengthEighths: state.lengthEighths, thicknessEighths: state.thicknessEighths,
         results: state.results ? rest : null,
         inventoryPng: state.results?.inventoryPng ?? null,
+        batchApply: state.batchApply,
       };
     }
     if (state.k === 'mask' && state.overlay) {
@@ -240,8 +244,13 @@ export function createCaptureSession(opts: SessionOpts = {}): CaptureSession {
     else if (state.k === 'batch' && state.photos.length === 0) await drafts.clearDraft();
   };
 
-  // Re-derive the mask bitset from the stored photo + params so Measure can run.
+  // Re-derive the mask bitset from a stored photo + frozen params. The decoded
-  const rederiveMask = (source: Source, params: MaskParams, stub: Omit<Mask, 'bitset' | 'params'>): Promise<Mask> =>
+  // dimensions are returned because batch Sources begin with dimensions unknown.
+  const rederiveMaskDetailed = (
+    source: Source,
+    params: MaskParams,
+    stub: Omit<Mask, 'bitset' | 'params'>,
+  ): Promise<{ mask: Mask; widthPx: number; heightPx: number }> =>
     new Promise((resolve, reject) => {
       if (typeof Worker === 'undefined') {
         reject(new Error('Worker unavailable'));
@@ -249,6 +258,8 @@ export function createCaptureSession(opts: SessionOpts = {}): CaptureSession {
       }
       const w = new Worker(new URL('../worker/mask.worker.ts', import.meta.url), { type: 'module' });
       let id = 0;
+      let widthPx = source.widthPx;
+      let heightPx = source.heightPx;
       const fail = (reason: string) => {
         w.terminate();
         reject(new Error(reason));
@@ -256,6 +267,8 @@ export function createCaptureSession(opts: SessionOpts = {}): CaptureSession {
       w.onmessage = (e: MessageEvent<WorkerOut>) => {
         const msg = e.data;
         if (msg.kind === 'decoded') {
+          widthPx = msg.w;
+          heightPx = msg.h;
           w.postMessage({ id: ++id, kind: 'mask', sheet: params.sheet, sensitivity: params.sensitivity } satisfies WorkerIn);
           return;
         }
@@ -266,17 +279,27 @@ export function createCaptureSession(opts: SessionOpts = {}): CaptureSession {
         if (msg.kind === 'ready') {
           w.terminate();
           resolve({
+            widthPx,
+            heightPx,
+            mask: {
               params,
               slabPx: msg.slabPx || stub.slabPx,
               bitset: msg.bitset,
               bbox: msg.slabPx > 0 ? msg.bbox : stub.bbox,
               slabBounds: msg.slabPx > 0 ? msg.slabBounds : stub.slabBounds,
+            },
           });
         }
       };
       w.postMessage({ id: ++id, kind: 'init', blob: source.blob } satisfies WorkerIn);
     });
 
+  const rederiveMask = (
+    source: Source,
+    params: MaskParams,
+    stub: Omit<Mask, 'bitset' | 'params'>,
+  ): Promise<Mask> => rederiveMaskDetailed(source, params, stub).then((r) => r.mask);
+
   // Legacy drafts (pre-axisBbox, with heading) carry no usable axis state;
   // fall back to the mask's own bbox.
   const draftAxisBbox = (d: Draft) => d.axisBbox ?? d.mask.bbox;
@@ -321,6 +344,7 @@ export function createCaptureSession(opts: SessionOpts = {}): CaptureSession {
         results: d.results
           ? { ...d.results, inventoryPng: d.inventoryPng ?? new Blob() }
           : null,
+        batchApply: d.batchApply,
       });
     } catch {
       set({ k: 'mask', source, control: { ...d.maskParams }, overlay: null, failed: true });
@@ -473,7 +497,8 @@ export function createCaptureSession(opts: SessionOpts = {}): CaptureSession {
       void persist();
     },
 
-    // #61: M1 Calculate on the calibration source only (batch apply is #62).
+    // #62: Calculate the calibration photo, then apply its frozen mask params
+    // to siblings. This stays in Measure; siblings never enter Mask controls.
     async calculate() {
       if (state.k !== 'measure') return;
       const { source, approvedMask, axis, lengthEighths, thicknessEighths } = state;
@@ -486,7 +511,7 @@ export function createCaptureSession(opts: SessionOpts = {}): CaptureSession {
       let pngBlob: Blob;
       let belowFloor = false;
       try {
-        const r = await encodeInventoryPng({ bitmap, mask: approvedMask, source });
+        const r = await encodeInventory({ bitmap, mask: approvedMask, source });
         pngBlob = r.blob;
         belowFloor = r.sourceBelowFloor;
       } catch {
@@ -497,7 +522,53 @@ export function createCaptureSession(opts: SessionOpts = {}): CaptureSession {
       if (pngUrl) URL.revokeObjectURL(pngUrl);
       pngUrl = URL.createObjectURL(pngBlob);
       const results: Measures = { ...base, inventoryPng: pngBlob, sourceBelowFloor: belowFloor };
-      set({ ...state, results });
+      const params = approvedMask.params;
+      const calIndex = calibrationIndex != null && calibrationIndex >= 0
+        ? calibrationIndex
+        : 0;
+      const batch = batchPhotos.length ? batchPhotos : [source];
+      const batchApply: BatchPhotoResult[] = batch.map((_, index) => (index === calIndex ? null : {
+        status: 'error',
+        message: 'Batch photo was not processed',
+      }));
+
+      // Process serially so each worker owns exactly one sibling photo and a
+      // failing decode/mask/encode cannot prevent later siblings from running.
+      for (let index = 0; index < batch.length; index++) {
+        if (index === calIndex) continue;
+        const photo = batch[index];
+        try {
+          const derived = await rederiveMaskDetailed(photo, params, {
+            slabPx: 0,
+            bbox: EMPTY_BBOX,
+            slabBounds: EMPTY_ABOX,
+          });
+          if (derived.mask.slabPx === 0) {
+            throw new Error('empty mask: no slab pixels detected');
+          }
+          const siblingSource: Source = {
+            ...photo,
+            widthPx: derived.widthPx,
+            heightPx: derived.heightPx,
+          };
+          const siblingBitmap = await createImageBitmap(photo.blob);
+          let encoded: { blob: Blob; sourceBelowFloor: boolean };
+          try {
+            encoded = await encodeInventory({ bitmap: siblingBitmap, mask: derived.mask, source: siblingSource });
+          } finally {
+            siblingBitmap.close();
+          }
+          if (encoded.sourceBelowFloor) {
+            throw new Error('PNG size floor: shorter side is below 800 px');
+          }
+          batchApply[index] = { status: 'ok', inventoryPng: encoded.blob };
+        } catch (error) {
+          const message = error instanceof Error ? error.message : 'unable to process photo';
+          batchApply[index] = { status: 'error', message };
+        }
+      }
+
+      set({ ...state, results, batchApply });
       void persist();
     },