M08: Thread opts_snapshot into process_images_inner for save-related reads

- Replace opts.foo with p.opts_snapshot.foo for safe read-only settings
- Migrated: save_images_before_face_restoration, save_images_before_color_correction,
  samples_format, return_mask, save_mask, return_mask_composite, save_mask_composite,
  grid_only_if_multiple, return_grid, grid_save, grid_format, grid_extended_filename
- Leave save_samples(), sample_hr_pass(), create_infotext(), metadata on shared.opts
- Behavior-preserving; no change to save paths or naming

Made-with: Cursor

docs/milestones/M08/M08_plan.md

@@ -1,3 +1,24 @@
 # M08 Plan — Snapshot Threading into process_images_inner
 
-(To be populated.)
+## Intent
+
+M07 introduced `p.opts_snapshot`. M08 threads it into the generation runtime by migrating safe read-only option access inside `process_images_inner()` from `shared.opts` to `p.opts_snapshot`.
+
+## Scope
+
+- **In scope:** Replace `opts.foo` with `p.opts_snapshot.foo` for save-related reads inside `process_images_inner()` only.
+- **Out of scope:** save_samples(), sample_hr_pass(), create_infotext(), Processed.__init__(), fill_fields_from_opts(), modules/images.py.
+
+## Migrated Options
+
+- save_images_before_face_restoration
+- save_images_before_color_correction
+- samples_format
+- return_mask, save_mask
+- return_mask_composite, save_mask_composite
+- grid_only_if_multiple, return_grid, grid_save
+- grid_format, grid_extended_filename
+
+## Invariants
+
+Same inputs → same outputs. File paths and naming unchanged. Extension compatibility preserved.

docs/milestones/M08/M08_toolcalls.md

@@ -2,4 +2,8 @@
 
 Implementation toolcalls for Cursor execution.
 
-(To be filled during milestone execution.)
+| Timestamp | Tool | Purpose | Files | Status |
+|-----------|------|---------|-------|--------|
+| 2026-03-11 | git checkout | Create/use m08-snapshot-threading branch | — | Done |
+| 2026-03-11 | search_replace | Migrate save-related opts to p.opts_snapshot in process_images_inner | modules/processing.py | Done |
+| 2026-03-11 | ruff check | Lint processing.py (pre-existing F811 in file) | modules/processing.py | Done |