Activity redesign 1/8: resolve change subjects server-side and generate the change-type list

[myieye]

Part 1 of 8 of the activity redesign (readable summaries + before/after diffs, #2170). The full assembled result of parts 1–6 — reviewed end-to-end by CodeRabbit and verified green — lived in #2434 (now closed); it was too large to merge in one piece, so it's split into a stacked sequence where each part is independently green and reviewable. This PR is the only one open; each next part gets its PR when its predecessor merges.

The sequence (each branch builds on the previous; part 6's tree is byte-identical to the reviewed #2434 head):

1. claude/activity-1-backend-change-info (this PR) — backend enrichment + change-type codegen. No user-visible change.
2. claude/activity-2-ws-code-chips — writing-system codes render as monospace chips app-wide (editor field labels, dictionary preview) for parity with the upcoming read-only diffs.
3. claude/activity-3-diff-components — the read-only diff-view component library (field-level before/after, inline text diff via @sanity/diff-match-patch, audio diffs) + storybook gallery + field-coverage guard tests. No consumer yet.
4. claude/activity-4-list-summaries — the activity list rows become readable summaries ("Apfel › apple · Set Definition (en) to …") grouped by entry, with per-author colours, badges, and bulk-create collapsing; exhaustiveness tests fail if a new change type lacks a summary.
5. claude/activity-5-detail-previews — the detail panel renders real before/after diffs through the diff components; single-entry create commits collapse to an assembled read-only view; per-card failure containment.
6. claude/activity-6-list-detail-layout — extracts Browse's responsive list↔detail shell into a shared ListDetailLayout and adopts it in Activity: resizable split panes on desktop, full-width list on mobile with full-screen detail + back-button support.
7. claude/activity-7-change-type-filter — replaces the flat ~65-row activity-type multi-select with a grouped, searchable, tri-state filter (sections by what a change touches, collapsed by default, hover "Only" shortcuts, empty selection = unfiltered, debounced instant apply).
8. claude/activity-8-author-filter — unifies the author facet onto the same shell and semantics (shared FacetFilter component, empty = unfiltered, ×-clear, "Only"), deleting the old 'all'-sentinel machinery and the "No authors → empty feed" state.

UI previews for the filter parts (7 and 8) — open in a browser:

• https://raw.githubusercontent.com/sillsdev/languageforge-lexbox/ff896559192ae3bb4f406ecde6272963a5de1142/docs/img/pr-activity-filter/filter-collapsed-groups.png
• https://raw.githubusercontent.com/sillsdev/languageforge-lexbox/ff896559192ae3bb4f406ecde6272963a5de1142/docs/img/pr-activity-filter/filter-group-expanded.png
• https://raw.githubusercontent.com/sillsdev/languageforge-lexbox/ff896559192ae3bb4f406ecde6272963a5de1142/docs/img/pr-activity-filter/filter-active-trigger.png
• https://raw.githubusercontent.com/sillsdev/languageforge-lexbox/38e5b4fb8369f730a83ce0d1e9c3e7c58b80eff1/docs/img/pr-activity-filter/filter-bar-unified.png
• https://raw.githubusercontent.com/sillsdev/languageforge-lexbox/38e5b4fb8369f730a83ce0d1e9c3e7c58b80eff1/docs/img/pr-activity-filter/author-filter-open.png
• https://raw.githubusercontent.com/sillsdev/languageforge-lexbox/38e5b4fb8369f730a83ce0d1e9c3e7c58b80eff1/docs/img/pr-activity-filter/author-filter-active.png

This part

Adds ActivityChangeInfoResolver: one batched pass per activity page that labels each change with the entity it's about (entry headword with homograph subscript, "headword › gloss" for senses, vocab object names), any item the change references only by id (the part of speech set, the semantic domain removed, the component linked), and the change's root entry so the frontend can group a commit's changes. Deleted objects are recovered from their latest snapshot (one Take(1) query per missing id) so a delete can still name its subject. ProjectActivity returns a materialized page (Task<ProjectActivity[]>) of enriched record copies (ChangeInfo is init-only) since the resolver batch-loads across the page — every consumer already materialized.

ChangeContext gains PreviousSnapshot (the entity's state just before the commit), the data needed for true before/after diffs (#2170).

A Reinforced.Typings generator emits a ChangeType string-literal union + knownChangeTypes array from the registered CRDT change types, using the same discriminator helper the runtime uses — parts 4 and 7's coverage tests are built on it, so a new change type can't silently ship without a summary or a filter group.

Tests: HistoryServiceActivityTests covers subject/target naming (homograph only-when-assigned, morph-type markers, sense numbering, deleted-object recovery, component endpoints, reorders) — 36 tests, all passing. Frontend impact is limited to regenerated types (additive) and a one-line HistoryView fix for the new required changeInfo property.

🤖 Generated with Claude Code

https://claude.ai/code/session_01Vm9mEUzcfgX4oUPAbhcfsj

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📝 Walkthrough

Walkthrough

Changes

Project activity now returns materialized pages enriched with resolved subjects and targets. Backend context handling, generated TypeScript contracts, invokable callers, viewer data construction, and extensive naming tests were updated accordingly.

Project Activity Enrichment

Layer / File(s)	Summary
Activity contract and batch resolution backend/FwLite/LcmCrdt/HistoryService.cs	ProjectActivity returns enriched arrays, ChangeContext tracks previous snapshots, and change-type key lookup is public.
Change-info label resolution backend/FwLite/LcmCrdt/ActivityChangeInfoResolver.cs	Loads current or recovered entities and resolves subjects, targets, headwords, sense labels, reorder metadata, and component endpoints.
Generated frontend contracts backend/FwLite/FwLiteShared/TypeGen/*, frontend/viewer/src/lib/dotnet-types/generated-types/LcmCrdt/*	Generates activity metadata interfaces and a complete ChangeType union with its known-value array.
Callers and validation backend/FwLite/FwLiteShared/Services/HistoryServiceJsInvokable.cs, backend/FwLite/LcmCrdt.Tests/*, frontend/viewer/src/lib/history/HistoryView.svelte	Updates callers and tests for materialized results and adds coverage for change-info naming across change scenarios.

Estimated code review effort: 4 (Complex) | ~45 minutes

Possibly related PRs

• sillsdev/languageforge-lexbox#1804: Changes the execution and materialization model of HistoryService.ProjectActivity.
• sillsdev/languageforge-lexbox#2093: Extends activity change-context handling.
• sillsdev/languageforge-lexbox#2357: Updates the activity querying surface and filters.

Suggested reviewers: rmunn, hahn-kev

Poem

I hop through changes, neat and bright,
With labels blooming into sight.
Old snapshots found, new types agree,
A tidy trail for history.
The rabbit stamps: “Enriched—whee!”

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 15.28% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Title check	✅ Passed	The title clearly summarizes the main backend change and generated change-type list.
Description check	✅ Passed	The description directly matches the PR's backend enrichment and change-type generation work.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch claude/activity-1-backend-change-info

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Build	Status	Details	Updated (UTC)
default (Inspect)	✅ No changes detected	-	Jul 22, 2026, 1:37 PM
e2e (Inspect)	✅ No changes detected	-	Jul 22, 2026, 1:46 PM

[myieye]

Note for the Argos review: this part is backend-only and intends zero visual change — the deterministic default build agrees (✅ no changes detected). The 5 diffs on the e2e build should therefore be environment noise (the e2e suite screenshots live pages with relative timestamps/seeded data, and it has flagged diffs on every recent build regardless of branch). If any of the 5 shows a real content difference rather than timestamp/data churn, please flag it here — that would mean the enriched activity payload is affecting the current UI, which would be a bug in this part.

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Generated by Claude Code

[myieye]

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Generated by Claude Code

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[hahn-kev]

looks good, I glossed over the change info resolver.