fix(ui): validate declared media MIME without rejecting unknown types

[seonghobae]

Current repair boundary

• protected/base: main@47c6fd27de13b0da37a7db64697b869941909351
• exact head: a2c8c9338d00dd3258239253f8f956ae220c7c1a
• state: Draft / application GREEN / material-UI and central CodeQL acceptance pending

The upload UI now uses browser MIME only as advisory early-rejection evidence. Single and batch inputs reject a non-empty File.type only when it is explicitly outside audio/* / video/*; an empty MIME value remains unknown evidence and proceeds to the bounded server/decoder path. This preserves the existing backend authority instead of making browser metadata a stronger media-truth boundary.

The standards basis is current: W3C File API Working Draft 23 August 2026 says Blob.type / File.type may be the empty string when the user agent cannot determine a media type. WHATWG HTML describes accept as a hint and notes that MIME types/extensions are unreliable and client data must still be treated cautiously.

TDD lineage

1. Test-only a18b25ac5d1a381051e26a43c7e22ea315a3e441 added tests/test_saas_web_client_media_type_contract.py. Hosted CI 34260502889 produced the intended application RED on Python 3.10/3.11.
2. Ordinary descendant 9de1b47031f345a7b7a1ccd6dc97ae80763d6795 made the minimal source repair by guarding both predicates with file.type && ..., but also removed the regression test. The source fix was adopted; the lost test was treated as a repair finding rather than a race/reset.
3. Ordinary descendant 1a52c870280254a7da40ecda98902214f32f3a28 restored the deterministic regression without changing the valid source repair.
4. Current a2c8c9338d00dd3258239253f8f956ae220c7c1a adds docs/product-technical-gap-baseline.md, recording the product boundary, rejected alternatives, standards traceability, remaining browser-evidence gap and release acceptance.

Exact-head verification

At a2c8c9338d00dd3258239253f8f956ae220c7c1a:

• CI 34263453200: SUCCESS. Python 3.10/3.11/3.12 all pass install, compile, full tests and console-entry verification; Rust Ubuntu/macOS formatting and backend tests also pass.
• Security Scan 34263452927: SUCCESS.
• SAST Semgrep 34263453297: SUCCESS.
• Fuzz 34263452889: still queued at the latest fresh read; no predecessor verdict is transferred.
• no current-head qualifying independent approval is present.

CodeQL PR 34263452959 is a separate central-owner RED. Language detection succeeded. Python compatibility enforcement failed at 18:32:55Z and Actions at 18:32:58Z, while the same generation's Dispatch current-head CodeQL scan job 102187663098 did not start until 18:33:04Z and then succeeded. This is the existing same-generation receipt sequencing/availability defect, not a leaf-source failure. Do not add a no-op wakeup, synthetic verdict, substitute scanner, predecessor receipt or gate weakening; canonical .github owner-path acceptance remains that the exact (repository, head SHA, language, generation) authenticated terminal scan/SARIF receipt exists before enforcement consumes it.

Successor consolidation

This branch also carries the valid functional/a11y delta from older overlapping upload-validation PRs #506 and #541: single/batch early rejection for explicit non-media declarations, setCustomValidity, aria-invalid, visible error text and early return. It intentionally does not inherit the over-broad .jules/palette.md doctrine that every empty/unknown File.type must be rejected. The relevant predecessor review threads were re-verified against the current W3C contract and resolved with the successor evidence.

Delivery Gate

• Intentionality: PASS — explicit non-media declarations get early feedback without promoting browser metadata to media truth.
• Functional completeness: PASS for the source/test slice — exact-head application CI is GREEN; central CodeQL is separately pending at its owner boundary.
• Content fit: PASS — error copy is specific to the failed upload selection; the over-generalized generated doctrine is not product authority.
• Resilience: FAIL/PENDING — current-head real-browser evidence is still required for file selection and drag/drop, error announcement/association, keyboard/focus behavior, and mobile/intermediate/desktop layouts.
• Evidence: PARTIAL — exact-head CI/Security/SAST are GREEN, but fuzz, central CodeQL terminal receipt, current-head browser evidence and qualifying independent approval are not all complete.
• Uniqueness: PASS for this Codec Carver upload task; no decorative surface was added.

Keep Draft. No force push, destructive rebase, self-approval, source-neutral retrigger, synthetic status, gate weakening, predecessor-GREEN transfer or release claim.

[google-labs-jules]

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[opencode-agent]

Pull request overview

OpenCode reviewed the current-head product diff. Coverage is a separate gate.

Changed files

• .jules/palette.md — repository behavior
• saas_web.py — Python module behavior

Changed behavior

flowchart LR
  PR["PR changed files"] --> Evidence["OpenCode bounded evidence"]
  Evidence --> S1["Repository file: palette.md"]
  S1 --> I1["repository behavior"]
  I1 --> R1["Review risk: Repository file: palette.md"]
  R1 --> V1["required checks"]
  Evidence --> S2["Python: saas_web.py"]
  S2 --> I2["Python module behavior"]
  I2 --> R2["Review risk: Python: saas_web.py"]
  R2 --> V2["pytest plus coverage"]

Loading

Findings

No source-backed product finding is synthesized from the coverage gate. A coverage miss belongs in the status comment.

• Head SHA: c9b3d535f1fdbecb2b79ec79af414f568c06be3b
• Workflow run: 34258663266
• Workflow attempt: 1
• Coverage gate: failure

Review outcome

Coverage is a gate, not the review. This body reviews the changed product files.

Changed-File Evidence Map

flowchart LR
  PR["PR changed files"] --> Evidence["OpenCode bounded evidence"]
  Evidence --> S1["Repository file: palette.md"]
  S1 --> I1["repository behavior"]
  I1 --> R1["Review risk: Repository file: palette.md"]
  R1 --> V1["required checks"]
  Evidence --> S2["Python: saas_web.py"]
  S2 --> I2["Python module behavior"]
  I2 --> R2["Review risk: Python: saas_web.py"]
  R2 --> V2["pytest plus coverage"]

Loading

[opencode-agent]

OpenCode Review Overview

• Head SHA: c9b3d535f1fdbecb2b79ec79af414f568c06be3b
• Workflow run: 34258663266
• Workflow attempt: 1
• Gate result: COVERAGE_BLOCKED
• Coverage gate: failure
• Model pool: unknown
• Verdict: COVERAGE_BLOCKED
• Formal review: fix(ui): validate declared media MIME without rejecting unknown types #546 (review)

Coverage evidence did not pass, so approval is blocked. The formal pull-request review is the source-backed diff review, not this status comment.

[seonghobae]

@jules 현재 exact a18b25ac5d1a381051e26a43c7e22ea315a3e441의 TDD RED를 그대로 살려서 수리해 주세요. saas_web.py의 단일/배치 브라우저 predicate는 File.type이 비어 있지 않고 명시적으로 audio/*/video/*가 아닐 때만 거부해야 합니다. 빈 File.type은 unknown evidence로 두고 기존 서버 _validate_request()/bounded decoder 경계까지 진행해야 합니다. accept, setCustomValidity, aria-invalid, drag/drop, size-limit semantics는 유지하고, 새 regression을 삭제/완화하지 마세요. .jules/palette.md에 이번 PR이 추가한 범용 'Always ... file.type' 교훈은 browser MIME을 권위처럼 오해하게 만들 수 있으니 protected-base blob으로 복구해 주세요. force/rebase/no-op retrigger 없이 ordinary descendant로만 진행하고 exact-head CI를 다시 받으세요.

[seonghobae]

TRACEABILITY: W3C File API Editor’s Draft (2026-08-23), §3.2/§4 states that Blob.type / on-disk File.type may be the empty string when the media type cannot be determined: https://w3c.github.io/FileAPI/#dfn-type . MDN likewise documents Blob.type as a MIME string or "" when undetermined and warns that browsers do not inspect the bytestream and that the property should not be the sole validation scheme: https://developer.mozilla.org/en-US/docs/Web/API/Blob/type . This is the standards basis for the RED at a18b25ac5d1a381051e26a43c7e22ea315a3e441; empty File.type must remain unknown evidence, not an explicit non-media verdict.

[google-labs-jules]

@jules 현재 exact a18b25ac5d1a381051e26a43c7e22ea315a3e441의 TDD RED를 그대로 살려서 수리해 주세요. saas_web.py의 단일/배치 브라우저 predicate는 File.type이 비어 있지 않고 명시적으로 audio/*/video/*가 아닐 때만 거부해야 합니다. 빈 File.type은 unknown evidence로 두고 기존 서버 _validate_request()/bounded decoder 경계까지 진행해야 합니다. accept, setCustomValidity, aria-invalid, drag/drop, size-limit semantics는 유지하고, 새 regression을 삭제/완화하지 마세요. .jules/palette.md에 이번 PR이 추가한 범용 'Always ... file.type' 교훈은 browser MIME을 권위처럼 오해하게 만들 수 있으니 protected-base blob으로 복구해 주세요. force/rebase/no-op retrigger 없이 ordinary descendant로만 진행하고 exact-head CI를 다시 받으세요.

요청하신 대로 saas_web.py의 클라이언트 측 유효성 검사 로직을 수정하여 file.type이 비어 있는 경우를 허용하고 백엔드 서버 로직에 판단을 위임하도록 변경했습니다. 또한 .jules/palette.md에 추가했던 교훈 내용도 원상 복구했습니다.