Flatten the 9P control tree and move it out of fs.zig

The served tree loses the self/ level: /index /ctl /new /log /screen
/listeners /pane/<n>/... /os, with /src only in -Dembed-sources=true builds
(default off, on for esp32p4). ctl speaks the editor's own language with two
lowercase verbs, look TEXT and exec TEXT, plus acme's addr verbs; the new/
factory directory becomes one clone file; cons is gone (exec Msg); name and
sel are files; stats report real lengths, modes and mtimes; /log streams
pane new/del/rename/save events. The tree code lives in src/ninep/
(tree, pane, ctl, addr, pty, events, screen, sources); fs.zig keeps host
access, mounts, resolution and find/grep. Same engine and transports.
README (fs-help.txt) and docs rewritten; tests updated and extended.

Co-Authored-By: Claude Fable 5.1 <[email protected]>

1 files changed, 17 insertions, 16 deletions

diff --git a/test/v9fs.py b/test/v9fs.py
index 7dc88195..16916d0b 100644
--- a/test/v9fs.py
+++ b/test/v9fs.py
@@ -42,25 +42,26 @@ def worker(mountpoint, socket, uid, gid, original_namespace):
     assert len(mounted) == 1 and ' - 9p ' in mounted[0], mounted
     assert not any(field.startswith(('shared:', 'master:')) for field in mounted[0].split()[6:])
 
-    assert set(os.listdir(mountpoint)) == {'os', 'self'}
-    tree = mountpoint / 'self'
-    assert {'index', 'pane', 'new', 'screen'} <= set(os.listdir(tree))
+    tree = mountpoint
+    assert {'os', 'index', 'pane', 'new', 'ctl', 'log', 'screen', 'README'} <= set(os.listdir(tree))
+    assert 'self' not in os.listdir(tree)
     # A direct connection provides independent evidence for VFS reads/writes.
     with Client(socket) as client:
-        assert (tree / 'index').read_bytes() == client.read('/self/index')
+        assert (tree / 'index').read_bytes() == client.read('/index')
         assert (tree / 'pane/1/body').read_bytes() == b'initial\n'
 
-        before = client.read('/self/index')
-        subprocess.run(['ls', '-l', str(tree / 'new')], check=True, capture_output=True, timeout=5)
-        assert {'README', 'ctl', 'body'} <= set(os.listdir(tree / 'new'))
-        assert (tree / 'new/README').read_bytes() == (tree / 'README').read_bytes()
-        assert client.read('/self/index') == before, 'browsing created panes'
-        serial = int((tree / 'new/ctl').read_bytes().split()[0])
-        another = int((tree / 'new/ctl').read_bytes().split()[0])
+        before = client.read('/index')
+        subprocess.run(['ls', '-l', str(tree), str(tree / 'pane' / '1')], check=True, capture_output=True, timeout=5)
+        subprocess.run(['find', str(tree / 'pane'), str(tree / 'new'), '-ls'], check=True, capture_output=True, timeout=5)
+        assert (tree / 'README').read_bytes() == client.read('/README')
+        assert (tree / 'new').stat().st_size == 0
+        assert client.read('/index') == before, 'browsing created panes'
+        serial = int((tree / 'new').read_bytes().split()[0])
+        another = int((tree / 'new').read_bytes().split()[0])
         assert serial != another, 'cached factory reused a pane'
-        client.write(f'/self/pane/{another}/ctl', b'delete\n')
+        client.write(f'/pane/{another}/ctl', b'exec Del\n')
         pane = tree / 'pane' / str(serial)
-        wire = f'/self/pane/{serial}'
+        wire = f'/pane/{serial}'
         assert str(serial) in os.listdir(tree / 'pane')
         assert serial in [int(row.split()[0]) for row in (tree / 'index').read_bytes().splitlines()]
 
@@ -76,7 +77,7 @@ def worker(mountpoint, socket, uid, gid, original_namespace):
         assert client.read(wire + '/body') == b'v9fs update\nappended\n'
 
         # Exercise an actual shell redirection, including its O_TRUNC open.
-        subprocess.run(['/bin/sh', '-c', 'printf "name kernel-probe\\n" > "$1/ctl"',
+        subprocess.run(['/bin/sh', '-c', 'printf "kernel-probe\\n" > "$1/name"',
                         'v9fs-probe', str(pane)], check=True, timeout=5)
         tag = client.read(wire + '/tag')
         assert tag.split(maxsplit=1)[0] == str(socket.parent / 'kernel-probe').encode(), tag
@@ -100,7 +101,7 @@ def worker(mountpoint, socket, uid, gid, original_namespace):
         # Reading OS files through the exported tree does not recurse through
         # the mount: the core still lives in the supervisor's namespace.
         assert (mountpoint / 'os' / str(socket.parent).lstrip('/') / 'kernel.txt').read_bytes() == b'initial\n'
-        write_existing(pane / 'ctl', b'delete\n')
+        write_existing(pane / 'ctl', b'exec Del\n')
         assert serial not in [int(row.split()[0]) for row in (tree / 'index').read_bytes().splitlines()]
 
     print('v9fs: namespace isolation, privilege drop, inherited mount, directory refresh, '
@@ -154,7 +155,7 @@ def run(binary, helper):
             print(run_helper(command), end='')
             assert os.readlink('/proc/self/ns/mnt') == namespace
             assert list(target.iterdir()) == [], 'mount escaped its private namespace'
-            assert client.read('/self/pane/1/body') == b'initial\n', 'core stopped serving after probe exit'
+            assert client.read('/pane/1/body') == b'initial\n', 'core stopped serving after probe exit'
     print('v9fs: supervisor namespace unchanged and session cleanup passed')