feat(lanes): add ccam lanes sync-base CLI (E2)

bin/ccam.js

@@ -1900,6 +1900,71 @@ async function cmdLanesRuntime(sub, args) {
       `lane #${laneId} running hook ${name} — follow it with: ccam lanes logs ${laneId} ${name}`
     );
   }
+
+  if (sub === "sync-base") {
+    const mode = laneArgs.includes("--check")
+      ? "check"
+      : laneArgs.includes("--continue")
+        ? "continue"
+        : "merge";
+    const branch = laneArgs.find((arg) => !arg.startsWith("--"));
+    const result = await post(
+      `/api/lanes/${laneId}/sync-base`,
+      { mode, branch },
+      { allowError: true }
+    );
+    if (result.status) {
+      console.error(`✖ sync-base → ${result.data?.error?.message || result.status}`);
+      process.exitCode = 1;
+      return;
+    }
+
+    if (result.code === 5) {
+      console.error(`✖ lane #${laneId} — MIGRATION NUMBER COLLISION (nothing merged):`);
+      for (const c of result.collisions) {
+        console.error(`  ${c.file} collides with ${c.collidesWith} — rename to ${c.suggestion}`);
+      }
+      process.exitCode = 5;
+      return;
+    }
+
+    if (result.code === 4) {
+      console.error(`✖ lane #${laneId} — MERGE CONFLICT (left in place).`);
+      console.error(`  conflicted: ${result.conflictedFiles.join(", ")}`);
+      console.error("  resolve, then: git add <resolved files> && git commit --no-edit");
+      console.error(
+        `  then: ccam lanes sync-base --continue ${branch ? branch + " " : ""}${laneId}`
+      );
+      process.exitCode = 4;
+      return;
+    }
+
+    if (mode === "check") {
+      if (result.devDelta === null) {
+        console.log("DEV_DELTA: unknown (no merge-base with origin/development)");
+      } else {
+        console.log(
+          `DEV_DELTA: ${result.devDelta.length} file(s) changed on origin/development since merge-base`
+        );
+        for (const f of result.devDelta) console.log(`  ${f}`);
+        if (result.overlap.length) {
+          console.log(
+            `DEV_OVERLAP: ${result.overlap.length} file(s) — the upstream delta touches the feature's files:`
+          );
+          for (const f of result.overlap) console.log(`  ${f}`);
+        } else {
+          console.log("DEV_OVERLAP: none");
+        }
+      }
+      console.log(`lane #${laneId} preflight vs origin/development: OK`);
+      return;
+    }
+
+    console.log(
+      `lane #${laneId} — synced with origin/development (re-enter the pipeline at the gates)`
+    );
+    return;
+  }
 }
 
 /**
@@ -2266,6 +2331,11 @@ const COMMAND_GROUPS = [
       ["lanes runtime", "[<id>]", "Slot, ports, service health and the last boot error"],
       ["lanes logs", "[<id>] <svc> [--tail N]", "Tail one of the lane's hook or service logs"],
       ["lanes hook", "[<id>] <name> [args…]", "Run a profile hook (ci-gate, e2e, migrate, …)"],
+      [
+        "lanes sync-base",
+        "[<id>] [--check|--continue] [branch]",
+        "Fetch + migration-collision preflight, or merge origin/development into the feature branch (--check: read-only; --continue: finish after a resolved conflict; bare: merge, branch defaults to the lane's current branch)",
+      ],
       [
         "lanes proof-link",
         "[<id>]",
@@ -3085,7 +3155,7 @@ async function runCommand(argv) {
       if (["reset", "remove", "purge"].includes(rest[0])) {
         return cmdLanesLifecycle(rest[0], rest.slice(1));
       }
-      if (["up", "down", "runtime", "logs", "hook"].includes(rest[0])) {
+      if (["up", "down", "runtime", "logs", "hook", "sync-base"].includes(rest[0])) {
         return cmdLanesRuntime(rest[0], rest.slice(1));
       }
       if (rest[0] === "proof-link") return cmdLanesProofLink(rest.slice(1));