fix(screenshots): regenerate screenshots from the current demo, remove older sets

tests/screenshot/run.mjs now clears PNGs a previous run left in its output directory and writes playground/screenshots/MANIFEST.json (output directory, sha256 per PNG, sha256 of the demo state rendered). One run produced the 24 PNGs in playground/screenshots/v1.15.0/ (12 surfaces x 2 themes, including the dark onboarding view removed in 1.18.1).

Removed the v1.10.0, v1.11.0, v1.14.0 and v2-mockup sets (77 PNGs) and tests/screenshot/shoot-mockup.local.mjs. Chose regenerate for the set the runner writes and delete for the rest, because the current runner cannot reproduce the older layouts, and the mockup script reads an HTML file that is not in the repository, so its output could never be regenerated from a clone.

README gallery, docs/playground.md and tests/screenshot/README.md now point at v1.15.0 and describe the 12 surfaces the runner captures. The manifest gate goes green: 4/4.

OCR (Apple Vision, local): 0 of 24 PNGs in the tree carry text from the older demo; known positives from 715950b were found (2 of 2).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

playground/screenshots/MANIFEST.json

@@ -0,0 +1,31 @@
+{
+  "generator": "tests/screenshot/run.mjs",
+  "dir": "playground/screenshots/v1.15.0",
+  "demoStateSha256": "0530e2312ece925d5e9cbd4ec0330476eee7e1d83cfb1060e53627341a7dc83a",
+  "files": {
+    "01-onboarding-empty-dark.png": "5ef4a9c1e264842e1ace08d590fc52ae1392c9b277a21e0aa220356d51379c1e",
+    "01-onboarding-empty-light.png": "bc0ddc7c386f3eb5d7d9a25f225563d10d917ac263c6df9571a0a8f558b4ebb7",
+    "02-project-overview-dark.png": "54448f7b968da367bedd5cfbd00322b8389b29a7b2e42d777cf0958225591450",
+    "02-project-overview-light.png": "eca5558a9e41edcfa7daa3d17833a8762e8769f7a1ec91d475934852db781a10",
+    "03-project-artifact-classify-dark.png": "7eef903788ba0b421849472df1257bd760ff947d4857bdd3bdb70136bea838fc",
+    "03-project-artifact-classify-light.png": "b015e585915f4274c2773441661aa9f1fc1afa7ce89f323be1f1ad983c8b0201",
+    "04-project-artifact-security-dark.png": "04010e82de61c2bf3ee28497b3e55866aa5ba7f0f1611bf1626b8b42d11b9aba",
+    "04-project-artifact-security-light.png": "28789b9a56c34f957287185d1803e401f53e09d72719115fb22ae88157734fdc",
+    "05-project-artifact-ros-dark.png": "b10739151c49c2c0181b0fdf25fd17eba3cb6ef8896bf9e94d3a0851b2f72faa",
+    "05-project-artifact-ros-light.png": "6c92839794ca15822d77d79d8943d1b22b97a602b240d4821d3145658a987f85",
+    "06-project-artifact-cost-dark.png": "eff9771c842f82a9ff5dcb377d5d729097d41da2ede74c6856e77b0db9c7a5c3",
+    "06-project-artifact-cost-light.png": "da4dc1ef35b77c9f132fb1425a01a6ca6927fb09970cf7c34a19eab5dbebf7d3",
+    "07-project-artifact-summary-dark.png": "2d2d822d97d2b59d30a19b170ae64ff7d7eca65f8a4b45faf802b3195dd91133",
+    "07-project-artifact-summary-light.png": "c887eb673ec49a8d9443c4da95041503c1133aed0981af756239c9651ba12331",
+    "08-project-import-modal-dark.png": "4acaba5bf92643b76867297c07eae4331c5b1d19c9aa51ec015641ed510058e8",
+    "08-project-import-modal-light.png": "a55af215c2c49b5a163c9d781ebb0927ffb862fcc82ee168151d5297e67ea480",
+    "09-project-search-dark.png": "5fcbbb1f19d94232dbe58fb3919466b1e6fcb54afdcad9949411f0eaf30f1e52",
+    "09-project-search-light.png": "c331e4b24c5fb36d7c12ccf5bf672656b972e75190082e6be031fb2232956c2f",
+    "10-home-dark.png": "c4180d9ef9c379e90759b4ec2f07e43f453e69aff1ef44ad696162f3455dafbd",
+    "10-home-light.png": "60c8907dfbfc3ac69797524bbe2fca2928379d15def16540436fe23b055fc117",
+    "11-catalog-dark.png": "7e211e14fbd6f1fcfe5eb895065675ccfe9d86f69f110d0c812123665bb2c891",
+    "11-catalog-light.png": "47439db2e9b941d9a9d6ade2244d63143c48abaeb619c779d1310dac597a6337",
+    "12-onboarding-prefilled-dark.png": "c443ae30e9f63d29f6153293b388bd6e6d9256ee414ddc3ab1f712a8af8a5c11",
+    "12-onboarding-prefilled-light.png": "bc0ddc7c386f3eb5d7d9a25f225563d10d917ac263c6df9571a0a8f558b4ebb7"
+  }
+}