Publish Claude Code source snapshot from a single baseline commit

Squash the imported source snapshot and follow-up documentation history
into one root commit so the archive starts from a single coherent state.

Constraint: Repository intentionally tracks an analyzed Claude Code source snapshot
Constraint: Author and committer must be instructkr <no-contact@instruct.kr>
Rejected: Preserve the four-step import/docs history | user explicitly requested one squashed commit
Confidence: high
Scope-risk: broad
Reversibility: clean
Directive: Keep future analysis and refactor commits separate from this archive baseline
Tested: git status clean; local history rewritten to one commit; force-pushed main to origin and instructkr
Not-tested: Fresh clone verification after push

src/bridge/flushGate.ts

@@ -0,0 +1,71 @@
+/**
+ * State machine for gating message writes during an initial flush.
+ *
+ * When a bridge session starts, historical messages are flushed to the
+ * server via a single HTTP POST. During that flush, new messages must
+ * be queued to prevent them from arriving at the server interleaved
+ * with the historical messages.
+ *
+ * Lifecycle:
+ *   start() → enqueue() returns true, items are queued
+ *   end()   → returns queued items for draining, enqueue() returns false
+ *   drop()  → discards queued items (permanent transport close)
+ *   deactivate() → clears active flag without dropping items
+ *                   (transport replacement — new transport will drain)
+ */
+export class FlushGate<T> {
+  private _active = false
+  private _pending: T[] = []
+
+  get active(): boolean {
+    return this._active
+  }
+
+  get pendingCount(): number {
+    return this._pending.length
+  }
+
+  /** Mark flush as in-progress. enqueue() will start queuing items. */
+  start(): void {
+    this._active = true
+  }
+
+  /**
+   * End the flush and return any queued items for draining.
+   * Caller is responsible for sending the returned items.
+   */
+  end(): T[] {
+    this._active = false
+    return this._pending.splice(0)
+  }
+
+  /**
+   * If flush is active, queue the items and return true.
+   * If flush is not active, return false (caller should send directly).
+   */
+  enqueue(...items: T[]): boolean {
+    if (!this._active) return false
+    this._pending.push(...items)
+    return true
+  }
+
+  /**
+   * Discard all queued items (permanent transport close).
+   * Returns the number of items dropped.
+   */
+  drop(): number {
+    this._active = false
+    const count = this._pending.length
+    this._pending.length = 0
+    return count
+  }
+
+  /**
+   * Clear the active flag without dropping queued items.
+   * Used when the transport is replaced (onWorkReceived) — the new
+   * transport's flush will drain the pending items.
+   */
+  deactivate(): void {
+    this._active = false
+  }
+}