Build the auto-commit engine

Every settled change on a git-mode board commits, debounced 2s past
drag/typing churn, staged whole-root with .gitignore respected.
GitCommitOperation reaches the vendored libgit2 directly (same 1.9.2
pin SwiftGitX resolves — importable, not duplicated) for
signature-capable commits; add-git's config materialization is gone,
identity resolves at commit time (repo-local config, else derived
default) per the 2026-07-31 ruling in 06. CommitAttribution
classifies per file off EchoLedger receipts: user identity on
app-mediated windows, Lanework External <[email protected]>
on foreign, the modified-by refinement (<slug>@agents.lanework
.invalid) when every foreign file agrees, heal-marked receipts split
into their own commit — window split foreign → heal → user.
Edit-session granularity: ~700ms saves stay uncommitted, staging
excludes open session folders (closure-resolved so mid-session moves
stage around the new location), session end nudges the debounce so
each session lands exactly one body commit. Flush-before-overwrite
gates on known-foreign windows and commits synchronously ahead of
the write; close/quit flush the pipeline via CloseFlushCoordinator's
committerFlush. index.lock backs off briefly then re-debounces
silently; clean tree no-ops; genuine failures ride the standing
history-suspension banner and retry next debounce. Abnormal repo
states (detached HEAD, merge/rebase/cherry-pick in progress) hold
the engine with a 15s re-check; unborn HEAD commits "Initial board
state" whole-tree; dirty tree at open catches up through the same
engine. Message seam (CommitMessageComposing) ships interim — the
semantic composer is the next card.

Discovery diffs HEAD against an in-memory index with rename
detection (git status alone never pairs a bare mv), and a failed
survey reads as "could not look", never "nothing changed".

46 new tests / 8 suites, all real repositories via bundled libgit2.
2240 tests / 383 suites green; InertGitTests untouched.

Claude-Session: https://claude.ai/code/session_01SR4XGjmBE16ZUYWpfFHXwY

Kanban/App/CardWindowHost.swift

@@ -523,6 +523,17 @@ struct CardWindowHost: View {
         bodyPresentation.flushEdits = { [session] in
             session.body.endEditSession()
         }
+        bodyPresentation.beginEdits = { [session] in
+            session.body.beginEditSession()
+        }
+        // **The stage-around registry's one wire** (06-history-undo.md ▸ Rules ▸ Auto-commit). The
+        // buffer announces its session boundary, the app model knows which board this card belongs
+        // to, and the committer knows what staging is; this line is the join, and it is the only
+        // place all three are in scope. A free-tier board — or any board with no repository — has no
+        // committer, so `setEditSession` records nothing and the buffer never learns the difference.
+        session.body.editSessionDidChange = { [appModel, ref] isEditing in
+            appModel.setEditSession(isEditing, for: ref)
+        }
         Self.configureRawSource(
             rawSource,
             body: session.body,