fix(portability): Windows aipass init + drone stdout (DPLAN-0194)

Two latent Windows portability bugs caught by the new e2e wiring harness:

- aipass init: _preflight_check ancestor walk crashed on OSError from
  un-enumerable Windows drive-root entries (pagefile.sys), swallowed by
  route_command as 'Unknown command: init'. Walk now skips unreadable
  entries (logged).
- drone @branch: crashed with UnicodeEncodeError ('charmap') printing a
  routed branch's captured output via Rich on cp1252 stdout. PYTHONUTF8
  only affects child interpreters; entry point now reconfigure()s the live
  stdout/stderr to UTF-8.

Pure portability — Linux/macOS behaviour unchanged. e2e suite 14/14 green
locally on Linux. Lets the 3-OS CI verify Windows.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

CHANGELOG.md

@@ -18,10 +18,12 @@ and this project uses [Calendar Versioning](https://calver.org/) in the format
   install + console scripts (T0), `aipass init` scaffolding (T1), a hook actually
   firing via the bridge with an observable `engine.jsonl` record (T2a), and
   `drone` resolving + subprocess-executing a real branch (T3). Runs on a 3-OS
-  matrix (ubuntu/windows/macos, `fail-fast: false`). Validated green on Linux;
-  Windows is **red-first by design** — the expected failures (unguarded `.venv`
-  symlink, `.venv/bin` vs `Scripts`, hardcoded `/tmp`) are the portability
-  fix-list, not regressions. (DPLAN-0194 / FPLAN-0239)
+  matrix (ubuntu/windows/macos, `fail-fast: false`). Ran red-first on Windows by
+  design and immediately earned its keep — it caught two real, *previously
+  uncovered* Windows wiring bugs (`aipass init` preflight + `drone` stdout
+  encoding, both fixed below). Notably the layers we most feared — clean-wheel
+  install (T0) and hook firing (T2a) — passed on Windows. (DPLAN-0194 /
+  FPLAN-0239)
 - **`drone rm` — provider-agnostic safe delete** — a contained recursive delete
   that lets agents clean up scratch dirs without tripping the `rm -rf` block.
   Deletes are confined to the project root and the system temp dirs (`/tmp` and
@@ -62,6 +64,24 @@ and this project uses [Calendar Versioning](https://calver.org/) in the format
 
 ### Fixed
 
+- **Two latent Windows portability bugs caught by the new e2e harness** — both
+  were always present in the code; they only surfaced now because this is the
+  first CI to run `aipass init` scaffolding and real-branch `drone` routing on
+  Windows (the old Windows CI ran an editable install, `aipass`-less, and only
+  routed to in-process modules, so both paths had zero Windows coverage). Pure
+  portability fixes — Linux/macOS behaviour is unchanged.
+  - **`aipass init` failed on Windows with a misleading "Unknown command: init".**
+    `_preflight_check` walks every ancestor of CWD up to the filesystem root
+    calling `iterdir()`/`is_file()`; at the Windows drive root a locked system
+    entry (e.g. `pagefile.sys`) raises `OSError`, which the CLI's `route_command`
+    swallowed and mislabeled. The ancestor walk now skips un-enumerable /
+    un-stattable entries (logged), so init proceeds normally.
+  - **`drone @branch` crashed on Windows with `UnicodeEncodeError ('charmap')`.**
+    `drone` resolved + subprocessed the branch correctly, then crashed *printing*
+    the captured output: Rich wrote Unicode through a cp1252 stdout. The existing
+    `PYTHONUTF8` guard only affected child interpreters, not the live process
+    streams — `drone`'s entry point now also `reconfigure()`s stdout/stderr to
+    UTF-8 in place. (DPLAN-0194)
 - **A release merge can no longer destroy the `dev` branch** — `drone @git merge`
   passed `--delete-branch` to `gh pr merge` unconditionally, so merging a
   `dev`→`main` PR deleted the persistent `dev` branch on the remote and stranded

src/aipass/aipass/apps/modules/init_flow.py

@@ -690,10 +690,24 @@ def _preflight_check() -> str | None:
             "This directory is an agent branch (has .trinity/passport.json).\n"
             "Agents are managed by 'drone @spawn', not 'aipass init'."
         )
-    # Block if inside an existing AIPass project (registry above us)
+    # Block if inside an existing AIPass project (registry above us).
+    # Walking up to the filesystem root can hit ancestors that can't be
+    # enumerated or stat'd — e.g. locked Windows system entries at the drive
+    # root (pagefile.sys) raise OSError. Skip those rather than crash; on
+    # POSIX everything up to / is readable so behaviour is unchanged there.
     for parent in [cwd] + list(cwd.parents):
-        for f in parent.iterdir():
-            if f.is_file() and f.name.endswith("_REGISTRY.json"):
+        try:
+            entries = list(parent.iterdir())
+        except OSError as exc:
+            logger.info("[init_flow] skipping unreadable ancestor %s: %s", parent, exc)
+            entries = []
+        for f in entries:
+            try:
+                is_registry = f.is_file() and f.name.endswith("_REGISTRY.json")
+            except OSError as exc:
+                logger.info("[init_flow] skipping unstattable entry %s: %s", f, exc)
+                continue
+            if is_registry:
                 return (
                     f"Already inside an AIPass project (found {f.name} at {parent}).\n"
                     "Use 'aipass init update' to upgrade an existing project."

src/aipass/drone/cli.py

@@ -1,3 +1,11 @@
+# =================== AIPass ====================
+# Name: cli.py
+# Description: Drone CLI entry point — console_scripts wrapper
+# Version: 1.0.0
+# Created: 2026-03-05
+# Modified: 2026-06-04
+# =============================================
+
 """
 Drone CLI — command-line interface for aipass.drone.
 
@@ -19,8 +27,21 @@ import sys
 # Windows terminals default to cp1252 which can't encode Rich's Unicode
 # characters (box-drawing, em dashes, arrows). Force UTF-8 before any
 # imports that trigger Rich output.
+#
+# PYTHONUTF8 only affects *child* interpreters launched afterward — it does
+# nothing for this process's already-open stdout/stderr, which were created
+# with the cp1252 codec at interpreter startup. Rich writes through those
+# live streams, so we must reconfigure them in place (Python 3.7+). Without
+# this, `drone @branch` crashes with UnicodeEncodeError ('charmap') when it
+# prints a routed branch's captured output on Windows.
 if sys.platform == "win32":
-    os.environ.setdefault("PYTHONUTF8", "1")
+    os.environ.setdefault("PYTHONUTF8", "1")  # for child subprocesses
+    for _stream in (sys.stdout, sys.stderr):
+        # getattr guard: streams replaced by a capture layer (e.g. pytest) or
+        # not backed by a TextIOWrapper simply lack reconfigure — skip them.
+        _reconfigure = getattr(_stream, "reconfigure", None)
+        if _reconfigure is not None:
+            _reconfigure(encoding="utf-8", errors="replace")
 
 from aipass.drone.apps.drone import main as _drone_main