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/Git/GitIdentity.swift

@@ -99,7 +99,12 @@ public extension GitIdentity {
     /// Characters an address part may carry, with everything else collapsed to `-`. Deliberately
     /// conservative rather than RFC-complete: the input is a Mac account name and a Bonjour host
     /// name, and the only job is that libgit2 accepts the signature and a git client renders it.
-    private static func addressComponent(_ raw: String, fallback: String) -> String {
+    ///
+    /// Shared with `CommitAttribution.agentIdentity(named:)` — a `modified-by` stamp is arbitrary
+    /// self-reported text and needs exactly this treatment to become an address local part
+    /// ("display name verbatim, email local part slugified", 06-history-undo.md). One slug rule for
+    /// both, so a name that is safe in a derived default cannot be unsafe in an agent's address.
+    static func addressComponent(_ raw: String, fallback: String) -> String {
         let allowed = CharacterSet.alphanumerics.union(CharacterSet(charactersIn: "-._"))
         let mapped = String(
             String.UnicodeScalarView(