feat: in-app frontmatter editing — the drawer becomes a guarded write site

[samkeen]

Closes #79.

The frontmatter drawer grows an Edit affordance: the raw YAML in a plain textarea with explicit Save (⌘⏎/⌘S) / Cancel (Esc), backed by one new façade op — Vault::write_frontmatter(note_ref, fm_yaml, base_revision), Vault::write's frontmatter sibling. Raw-text-first by design: a form round-trip would be a silent rewrite of the human's YAML (W4/W5), so B2 splices the buffer verbatim between the fences and judges nothing.

Core (b2-core)

• ParsedNote::replace_frontmatter — the byte-honest splice mirroring replace_body: only the bytes between the fences change; every body byte is preserved by construction. The one mechanical touch is a missing final newline (so the closing fence stays on its own line).

• Vault::write_frontmatter — same shape as write: whole-file content-hash revision guard (body saves and frontmatter saves guard each other with no new concurrency story), splice, model-free re-projection. An unchanged body keeps its chunks and vectors — a frontmatter save never re-embeds; the notes row and typed edges re-derive from the new block.

• Two refusals, validated on the re-parsed spliced candidate before any byte reaches disk:

  • a changed/removed/duplicated b2id (new Error::FrontmatterIdentity) — L1, the one line B2 protects. Re-quoting the same id passes (identity, not bytes);
  • a top-level --- line (Error::Frontmatter) — it would close the block early and leak the rest into the body, and the body is not this op's to change.

  Everything else saves — malformed YAML included: it round-trips verbatim and projects best-effort, exactly as the same edit made in vim would.

• Warn-don't-block surfacing: ParsedNote::frontmatter_readable + NoteView.frontmatter_readable flag a block that doesn't read as YAML metadata. Computed at read time, so the fs-watch reconcile path raises the identical warning for an external hand-edit — the case In-app frontmatter editing — a self-healing FM write site #79 is really hardening against (the Invalid YAML frontmatter triggers a b2id re-stamp loop (file grows every reindex; desktop can loop on it) #75 self-healing stance, extended).

Adapters (thin, per E3)

• desktop: one write_frontmatter command (model-free, write_note's posture, outside the embed slot) + actionable error mappings; CLI: matching user_message arms.
• ui: drawer Edit → mini-editor with inline refusal messages, a Reload / Keep-mine conflict strip, a ⚠︎ flag on the drawer toggle for unreadable YAML, and the render carve-out + edit guards so the live buffer is never rebuilt or silently discarded (keyboard paths throughout, per K1). No autosave, deliberately: half-typed YAML isn't a body sentence, and the b2id guard wants a deliberate save to refuse cleanly.

Docs

W3's on-command write enumeration (invariants.md), the root CLAUDE.md write list, and the desktop CLAUDE.md model-free-ops list gain the new write site — deliberate amendments, sanctioned by #79.

Tests

8 new core integration tests (tests/write_frontmatter.rs: byte-honesty, identity guard, fence refusal, conflict chain, malformed-YAML round-trip + heal, edges-without-reembed, model-free posture, mixed body/FM revision chaining), 5 new note.rs unit tests, 2 new desktop command tests. Full core suite (31 binaries), desktop suite (44 tests), clippy, fmt, tsc + vite build, and the frontend pure-logic suite all green.

Extracted follow-ups (so this closes #79 cleanly)

• New-note template keys: drop type:, keep created:, namespace neither #80 — new-note template keys: drop type:, keep created:, namespace neither (the question from In-app frontmatter editing — a self-healing FM write site #79's comment thread; needs a deliberate data-model.md §1 amendment).
• Reindex-time diagnostic: surface cross-note b2id collisions (and identity restamps) instead of silently shadowing #81 — reindex-time diagnostic for cross-note b2id collisions and identity restamps (the one In-app frontmatter editing — a self-healing FM write site #79 pathology this PR doesn't cover: it needs index-wide knowledge, and the in-app path is now closed by the guard).

🤖 Generated with Claude Code

https://claude.ai/code/session_013nEUZMKhLH5DRUT2z3g2Nr

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Generated by Claude Code

Summary by CodeRabbit

• New Features

  • Added a frontmatter mini-editor (Save, Cancel, Reload, Keep Mine) with an unreadable warning and inline conflict/error messaging.
  • Introduced model-free frontmatter saving that preserves the note body and maintains revision conflict contracts.
  • Extended UI/IPC to support frontmatter-only writes and to reflect frontmatter readability.

• Bug Fixes

  • Improved frontmatter parsing/readability detection while keeping raw bytes round-trippable.
  • Enforced protection of the note identity by refusing frontmatter edits that change, remove, or duplicate b2id.
  • Strengthened write validation (including fence-line --- handling) and revision chaining behavior.

• Tests

  • Added integration coverage for frontmatter write invariants and edge cases.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

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• ui/src/main.ts

🚧 Files skipped from review as they are similar to previous changes (1)

• ui/src/main.ts

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📝 Walkthrough

Walkthrough

Adds guarded frontmatter persistence with YAML readability tracking, identity and revision validation, desktop IPC wiring, and a frontend mini-editor with save, conflict handling, navigation guards, and unreadable-frontmatter warnings.

Changes

Frontmatter editing

Layer / File(s)	Summary
Core frontmatter parsing and contracts crates/b2-core/src/error.rs, crates/b2-core/src/note.rs, crates/b2-core/src/vault.rs	Tracks YAML readability, centralizes reparsing, preserves raw bytes, validates top-level b2id, and exposes readability through NoteView.
Guarded frontmatter persistence crates/b2-core/src/vault.rs, crates/b2-core/tests/write_frontmatter.rs, CLAUDE.md, docs/design/invariants.md	Adds revision-guarded frontmatter splicing that preserves the body, rejects fence and identity violations, reprojects metadata, and tests malformed YAML, relations, vectors, projection-only vaults, and chained writes.
Desktop command and error wiring crates/b2-cli/src/main.rs, crates/b2-desktop/src/commands.rs, crates/b2-desktop/src/error.rs, crates/b2-desktop/src/main.rs, crates/b2-desktop/CLAUDE.md	Exposes write_frontmatter through Tauri, delegates through a model-free vault, maps errors, registers the command, and updates wiring documentation.
Frontend mini-editor UI ui/src/api.ts, ui/src/main.ts, ui/src/render.ts, ui/src/state.ts, ui/src/types.ts, ui/style.css	Adds raw YAML editing, save/cancel/reload/keep-mine controls, conflict handling, edit guards, readability warnings, IPC integration, and styling.

Estimated code review effort: 4 (Complex) | ~60 minutes

Possibly related issues

• Desktop & CLI editor follow-ups (live-preview block widgets · frontmatter editing · b2 write · orphan re-link) #69 — Covers the broader frontmatter-editing work implemented here.

Possibly related PRs

• AlteredCraft/B2#53 — Overlaps with navigation and editor-state guards.
• AlteredCraft/B2#62 — Overlaps with frontmatter parsing and field extraction.

Poem

A rabbit edits YAML with care,
Keeps every byte exactly there.
The b2id stays, the body rests,
Conflicts hop through guarded nests.
Save and reproject bright—
Frontmatter lands just right.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly describes the main change: adding in-app frontmatter editing as a guarded write path.
Linked Issues check	✅ Passed	The PR implements byte-preserving frontmatter editing with revision guards, b2id protection, warnings, and UI/command support for #79.
Out of Scope Changes check	✅ Passed	The changes are focused on frontmatter editing, related guards, UI, docs, and tests; no unrelated scope appears introduced.
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%.

✨ Finishing Touches

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🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch claude/gh-79-review-5d8e7q

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[coderabbitai]

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@ui/src/main.ts`:
- Around line 1470-1472: Update the analogous post-embed reread in
autoIndexOnOpen to require both !state.editing and !state.fmEditing before
calling api.readNote, preserving the existing reread behavior when neither
editor is active.

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Fix all unresolved CodeRabbit comments on this PR:

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ℹ️ Review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro Plus

Run ID: 9e6666bb-322e-4bc9-9575-cefbe841ecbb

📥 Commits

Reviewing files that changed from the base of the PR and between 7978842 and f5f48a5.

📒 Files selected for processing (17)

• CLAUDE.md
• crates/b2-cli/src/main.rs
• crates/b2-core/src/error.rs
• crates/b2-core/src/note.rs
• crates/b2-core/src/vault.rs
• crates/b2-core/tests/write_frontmatter.rs
• crates/b2-desktop/CLAUDE.md
• crates/b2-desktop/src/commands.rs
• crates/b2-desktop/src/error.rs
• crates/b2-desktop/src/main.rs
• docs/design/invariants.md
• ui/src/api.ts
• ui/src/main.ts
• ui/src/render.ts
• ui/src/state.ts
• ui/src/types.ts
• ui/style.css