M11-03: User-facing failure modes

[DrunkOnJava]

Created from the roadmap audit in TODO.md.

Source: https://github.com/DrunkOnJava/rvt-rs/blob/main/TODO.md#L1205
Tracking commit: 1ec8105

Scope

Labels: priority:P0, type:feature, area:product

• For unsupported inputs, show one of:
  • unsupported Revit version
  • supported file but unsupported model layout
  • corrupt file
  • partial decode
  • scaffold-only export
  • parser bug, please report
• Include a diagnostics download button.

Acceptance criteria:

• No user gets an apparently successful empty export without a warning.
• CLI exits non-zero in strict mode for unsupported real-model export.

Definition of done

• The TODO acceptance criteria for this section are implemented or explicitly superseded by a linked decision.
• Tests, fixtures, or documentation are added at the level appropriate to the change risk.
• User-facing behavior and limitations remain honest in README/docs/viewer messaging.
• Relevant CI checks pass before the issue is closed.

[DrunkOnJava]

Starting implementation now. I will add an explicit user-facing failure-mode classification across rvt-inspect JSON/text and viewer status, reusing the diagnostic terms added in cbc766e. Scope is limited to classification and messaging; decoder behavior stays unchanged.

[DrunkOnJava]

Implemented in 4ab7326.

Changes:

• Added stable rvt-inspect JSON failure_mode classification with kind/title/summary/severity.
• Added human CLI Failure mode section.
• Added JSON error output for corrupt/unreadable input with failure_mode.kind = corrupt_file.
• Added viewer file-status Mode row for unsupported Revit versions, unsupported model layout, corrupt/unreadable files, partial decode, scaffold-only export, parser-bug/report cases, and supported-profile output.
• Documented the failure-mode kinds in docs/diagnostic-semantics.md and docs/inspect.md.

Validation:

• cargo test --test rvt_inspect_cli
• cargo clippy --bin rvt-inspect --test rvt_inspect_cli -- -D warnings
• npm run typecheck (viewer)
• npm run build (viewer; existing >500 kB chunk warning only)
• git diff --check
• anti-stub scan over touched files

I will close this after the main-branch checks for 4ab7326 finish green.